Stator/Timing base condition question, re. rough idle

[Mickyfinn]

Hi

Started a new thread because the "right in the middle of it" carb question thread was moving way off the original direction. Thanks to all who helped on that one, now for the current dilema...

1990 Johnson 120 V4 with an intermittant coughing/sneezing/dying out at only an idle problem. Sometimes it runs perfectly at an idle, then it will start sputtering and stalling. I've been through the fuel system pretty thoroughly and I'm checking the electrical. New plugs and wires, strong spark on each cylinder when I tested them. Maybe dropping a cylinder, but can't seem to find it. Idle timing dead on and idle speed where it should be. Carbs rebuilt and seem pretty tight and true.

I pulled the flywheel to look for possible worn wires/shorts coming off the stator or timer base and it mostly looked pretty good. There is some corrosion on the flywheel magnets plus the same and what looks like black paint on the stator magnets that I'll clean off. I removed the stator to look at the timer base it appeared to be in decent shape except for a small hole in the side (@ 1/8"+ oval) that I can see rusted/corroded metal inside. The hole is pretty clean, not like a burn through. The rusted metal underneath is one of the pickups. Any opinions on repair/replacement? Money is tight enough that I don't want to change it if I don't have to. I was thinking some liquid electrical tape in the hole to seal it up. How likely is this to cause the intermittant idle issue?

I also found a wire coming out of the stator that had the insulation cracked right where it meets the base of the stator. The wire doesn't look damaged, just the casing. Not that I know what I'm doing.... but I tested the wires coming out of the stator with an ohmmeter. None of the wires grounded out to the base but I did notice that between the two orange wires I had 95 ohms resistance, but between the two yellow wires (one of the yellows had the broken casing) there was only .9-1.0 ohms resistance. Anyone know if this sounds right? Between the two brown wires in the plug there were 400 ohms.


Please feel free to add any input or suggestions for the rough idle. I've checked too many things so far to list them, but throw some out and I'll try the things I haven't checked yet!
Thanks

 

[mikesea]

Re: Stator/Timing base condition question, re. rough idle

Im wondering if you might be getting too much fuel at idle.By any chance is your primer on,paritally on or passing fuel.

 

[Mickyfinn]

Re: Stator/Timing base condition question, re. rough idle

Funny, I was originally thinking I was possibly running lean...Engine has 30 hours on a new rebuild (done three years ago and sat unused since the rebuild til I bought it this spring) when it was supposedly bored oversize (not sure if actually true and difficult to find out for sure, but it was sold as bored out). I was thinking that it might need the idle jets replaced to make it more rich and asked this question earlier. The general consensus was that they were probably fine and it was something else. Also, it does seem to idle very smoothly, at the correct speed for several minutes at a time and then sporadically run like it was dropping a cylinder for a bit, then run fine again. My thought was that it would run more consistantly rough if just too lean....make any sense??

I tested the primer, which seems to be working fine, then installed new diaphragm/o-rings. The lever is inline to the solenoid.

Thanks

Evan

 

[Mickyfinn]

Re: Stator/Timing base condition question, re. rough idle

May have found the problem. I put some liquid electrical tape on the hole in the timing base and over the broken wire casing on the stator and re-assembled. I fired it over to check the idle timing again and it was running poorly and it seemed as if the timing mark was jumping occasionally from 8 ATDC to around 14 ATDC. It did eventually even out but I decided to check the other cyl with the timing light to make sure they were firing. The cyl. below #1 (can never remember how the pattern goes) was not firing at all. I turned it off and checked all the connections and it still did not fire. Motor was doing its general roughness thing but not stalling. I brought the engine speed up to @ 1800 rpm and it started to flash sporadically. Brought the speed back down, no flash. Turned it off, fired it back up and it's running smooth and now firing on that cyl. Did this a few more times but can't get it to drop out again. I'm going to take the boat out for a spin with the timing light to see if it is dropping out. By the way, the coils are all new within the last few months.

Assuming it will, any suggestions on where to go from here? I hate to start just changing parts, especially those ones. I'm open to testing procedures, but can't really make much sense of the Seloc book and may not have the right testing equipment (just have a nice digital multimeter).

Thanks!!
Evan

 

[ezeke]

Re: Stator/Timing base condition question, re. rough idle

I'm not clear on how you are allowing for QuikStart in your analysis, could you elaborate?

 

[Mickyfinn]

Re: Stator/Timing base condition question, re. rough idle

Hi ezeke,

I guess I would say I'm not allowing for Quick Start at all. Didn't know the motor had it, and not really sure what it is? No one has mentioned it before, but I've come across it while digging though the forum. If you would, please tell me what it is and how it affects the motor, especially the idle.

As for an update, nothing has changed with the intermittant sputtering. I took the timing light out and checked all the cylinders as it idled and died, and just could not see any cylinder dropping out. I'm still not convinced it's not happening, it's just that if one or more was dropping out, I couldn't tell because it would pick right up again, like it was skipping a beat now and then. There must be a diagnostic tool out there that could read all four cylinders and tell if this is happening. I may have to bite the bullet and bring it somewhere. In the meantime, feel free to chime in with any insight.


Thanks,
Evan

 

[ezeke]

Re: Stator/Timing base condition question, re. rough idle

The 90 degree big bore V4 loopers have QuikStart and S.L.O.W. features built in to the ignition system.

When the engine is started cold, or less than 96? F. the timing is advanced to allow for easier starting. The advance stays in place until the engine warms to 96? or the speed is advanced to >1100 RPM, whichever comes first.

Every time the engine is started, the QuikStart advances the timing for 5 seconds even if the engine is warm.

Any attempt to set or adjust timing without disabling or allowing for QuikStart will make things dramatically worse.

 

[Mickyfinn]

Re: Stator/Timing base condition question, re. rough idle

Thanks for the info. Nice to know the features my motor has! I didn't disable the feature when setting the timing, but the motor had been running for several minutes with muffs on. I did check the timing on the water last night after I had been running it around for some time and it was still dead on. I kept switching the timing lite to different cyl. to see if I could find one dropping out. I couldn't tell. That does make some sense though of the erratic timing I mentioned previously. The motor was cold and just started when it was off, then it eventually settled down to where it should be. Still not sure why I wasn't getting any spark on the other cylinder for so long, then to have it come back and not drop again.

Just out of curiosity, where is the QuickStart controlled from, the power pack?

Thanks

 

[ezeke]

Re: Stator/Timing base condition question, re. rough idle

Both QuikStart and S.L.O.W. are controlled by the powerpack. The port temperature switch has the extra sensor and black and white lead in addition to the normal tan wire for the warning horn.

Best bet is to let the engine warm up with the QuikStart before using the warm up lever too much. That way you don't cut it off at 1100 RPM.

 

[Mickyfinn]

Re: Stator/Timing base condition question, re. rough idle

Cool, I'll keep that in mind. Any thoughts on the most likely suspect for an intermittant sneezing idle? I pulled it apart to look for wires grounding out, found the things I mentioned above but no other visable problems. It runs smooth as glass for a period of time, sometimes short, sometimes several minutes, then it starts to cough/sneeze, dies and recovers, etc and then might die or stay running. Sometimes it does it right from starting, sometimes not. It's really starting to drive me crazy, especially when it dies tying to put in on the dock.

I'm thinking of biting the bullet and replacing the power pack. I figure I'll probably need to eventually, but I'm curious to know if that's where you would go first. I've pretty thoroughly been through the fuel system and it seems like it is just skipping a "beat" and catching back on.

Any thoughts?

 

[ezeke]

Re: Stator/Timing base condition question, re. rough idle

If you are sure you don't have an air leak somewhere, and the carburetors are carefully synchronized, I would take each ignition coil off and thoroughly clean all of the contact surfaces. At $200. or more I would clean and check all of the engine wiring first.

BTW, From time to time, a bad ignition switch or kill switch has turned out to be lightly grounding the kill circuit intermittently.

 

[Mickyfinn]

Re: Stator/Timing base condition question, re. rough idle

Yeah, I know it's potentially throwing good money for bad but I'm getting to that point. I rebuilt the carbs, put on all new fuel and primer hoses, the boat has a brand new fuel tank, lines, filter, hoses, etc. I checked all the recirc valves and lines, rebuilt the solenoid, pulled the pump apart and checked it (didn't test fuel pressure but it runs so well above an idle), checked to make sure I have the right jets installed (still thinking I might try re-jetting the idle, I was going to go more rich, but it runs sooo well when it's running well that I would think it would be more consistantly rough if it were just jets). The only thing I haven't done is take off the intake manifold and check that and the reeds, but it was just rebuilt, I would hope he wouldn't put it together with bad reeds. All in all, given the intermittant nature of the problem, I'm leaning towards an electrical issue. I'm obviously new to marine engines, but I've been repairing equipment for years and most fuel issues tent to be more consistant. Lord knows this Johnson is about as complicated as they come, but I would assume the principal is the same...

Given that the mechanic who did the rebuild has turned out to be pretty sloppy in other areas I've found (and he came so highly recommended....ugh!), I suppose it might be leaking somewhere in the crankcase or manifold, but wouldn't that also affect the higher speeds as well?

All that fuel work has been my labor for the last month or so. Now I've moved over to the electrical side of things. The ignition switch is new, the old one failed about a month ago. I had this problem before I switched it. Yesterday I pulled the flywheel off to check for any worn wires or visible problems. I did find the small hole in the side of the timing base and the cracked wire insulation on the stator but no other visible problems. I was hoping that it might have been occasionally arcing out of one of those so I tried some liquid electrical tape, no change in the problem.

So, that leaves me at the point where I drive the boat some distance and pay someone I don't know anything about to try to test and repair an intermittant problem, (not to mention when I might ever get it back). That could be just as costly as changing out parts, and at least I'll have some spare parts if I do it myself. I just hate doing that and it's really bugging me. This forum has been an incredible education and you guys have already saved my *** on several occasions!

Sooo, given all that, any suggestions? The way I see it, if I start changing electrical parts I've got four avenues to choose from, Power pack, rectifier/regulator, stator, and timing base (coils and plug wires are new). Out of the four, any stand out as being more troublematic, especially with the intermittancy issue, and also take into account something that would be affected by motor speed given that it runs smooth as glass all the time above @2200 rpm.

Thoughts???

 

[Mickyfinn]

Re: Stator/Timing base condition question, re. rough idle

Yeah, I know it's potentially throwing good money for bad but I'm getting to that point. I rebuilt the carbs, put on all new fuel and primer hoses, the boat has a brand new fuel tank, lines, filter, hoses, etc. I checked all the recirc valves and lines, rebuilt the solenoid, pulled the pump apart and checked it (didn't test fuel pressure but it runs so well above an idle), checked to make sure I have the right jets installed (still thinking I might try re-jetting the idle, I was going to go more rich, but it runs sooo well when it's running well that I would think it would be more consistantly rough if it were just jets). The only thing I haven't done is take off the intake manifold and check that and the reeds, but it was just rebuilt, I would hope he wouldn't put it together with bad reeds. All in all, given the intermittant nature of the problem, I'm leaning towards an electrical issue. I'm obviously new to marine engines, but I've been repairing equipment for years and most fuel issues tent to be more consistant. Lord knows this Johnson is about as complicated as they come, but I would assume the principal is the same...

Given that the mechanic who did the rebuild has turned out to be pretty sloppy in other areas I've found (and he came so highly recommended....ugh!), I suppose it might be leaking somewhere in the crankcase or manifold, but wouldn't that also affect the higher speeds as well?

All that fuel work has been my labor for the last month or so. Now I've moved over to the electrical side of things. The ignition switch is new, the old one failed about a month ago. I had this problem before I switched it. Yesterday I pulled the flywheel off to check for any worn wires or visible problems. I did find the small hole in the side of the timing base and the cracked wire insulation on the stator but no other visible problems. I was hoping that it might have been occasionally arcing out of one of those so I tried some liquid electrical tape, no change in the problem.

So, that leaves me at the point where I drive the boat some distance and pay someone I don't know anything about to try to test and repair an intermittant problem, (not to mention when I might ever get it back). That could be just as costly as changing out parts, and at least I'll have some spare parts if I do it myself. I just hate doing that and it's really bugging me. This forum has been an incredible education and you guys have already saved my *** on several occasions!

Sooo, given all that, any suggestions? The way I see it, if I start changing electrical parts I've got four avenues to choose from, Power pack, rectifier/regulator, stator, and timing base (coils and plug wires are new). Out of the four, any stand out as being more troublematic, especially with the intermittancy issue, and also take into account something that would be affected by motor speed given that it runs smooth as glass all the time above @2200 rpm.

Thoughts???

 

[Dennisanoka]

Re: Stator/Timing base condition question, re. rough idle

When I think that I have exhausted all possibilities, I probably have over looked something. One issue that concerns me is that in your very first post you mention that you bought this engine re-built and from day one it has not run properly. Consequently I would suggest going back to square one and don't assume anything. Does it have proper compression in each cylinder? Does it have spark to all cylinders, and in the proper sequence and is the spark sufficient at low rpm? You'll have to make a spark tester like the ones mentioned here on this site. And in your first post you mentioned attempting to ream out some jets, did you actually change them, AT ALL? It seemed like you had tried pretty hard. That is what I would do, start with the first two and re-consider if you may have successfully reamed out some jets, even just a little.

 

[Mickyfinn]

Re: Stator/Timing base condition question, re. rough idle

Yeah, I been having that feeling for some time now. You guys have been a great education about this motor. With all the things I have done, I know there's certainly more I haven't. That's why I keep asking. I keep thinking it's something stupidly obvious that my inexperience has overlooked!

As for compression, it was one of the first things I checked, all four @ 150lbs, within 2 lbs of each other. Early on I built a four post spark tester I saw a picture of here. I set each one at exactly 7/16" and saw some cyls that weren't firing right. At that point, I was thinking weak coils, but maybe just bad grounds. I cleaned all the contacts, including filing the mounts on the block. I also took all the wires off the strip under the power pack (one by one so as not to mix them up), inspected and cleaned them and the contacts. It didn't help with the weak/missing spark. The coils on the motor didn't match each other either, same shape just different mfg. I figured there were worse things than investing is new coils so I picked up a set of OMC coils only to find that it didn't help. I decided to hunt down a real adjustable spark tester to check them and they all had strong spark tested at 1/2". I actually reinstalled the old coils to find they tested fine as well. I guess I didn't make the homemade tester well enough. Because the four way tester wasn't working right, I couldn't really test the order, unless there's a better way you know for me to try?? I've read threads about wires being crossed messing up the order, but it seems to affect the firing throughout the rpm range, not just the idle. Mine runs smooth as glass above 2200 rpm all the time so I wouldn't think that would be the issue.

The other day I finally got my hands on a timing light to check the spark with the plugs in and running. I don't think I'm good enough to tell which came first, the cyl not firing slowing the motor or the motor slowing and delaying the flash. It does seem like it might be firing in the wrong order or even possibly two cyls at the same time. It almost seems to lock the motor when it sneezes sometimes. I read a thread describing a bad powerpack that was doing that, found it interesting but hard for me to test for.

As for the carbs, I did get pretty heavy handed with a wire on one of the pickup tubes but never on any of the jets or other orifaces, just air and cleaner. It still strikes me as completely crazy that the pickup tube for the idle has an opening that's smaller than the brass oriface (ever so slightly, but definitly smaller) but being that all four are exactly the same I'm guessing they're the way they're supposed to be. After I put them all back, it ran just the same as it did before I took them apart. Also, at this point after really listening and paying attention to it for so long now it seems too random and intermittant to keep me thinking fuel. It quite often runs smooth as glass for some length of time then instantly changes and sputters and coughs. Sometimes it will clear up but mostly it will stay like that for some time. I would think fuel issues would be more consistant. It also always starts back up instantly, sometimes running normally and well.

I spent quite some time the other day pulling the stator and timing base off, cleaning them and looking for visible damage to them and all the wires in the ignition system. I wrote above what I found, it could still be part of the problem. Today, I disconnected the white/black wire to see if the Quickstart was a factor, didn't seem to make any difference. I did try to do another test (I was looking at the troubleshooting section on Rapair.com) checking the voltage of the orange wires coming from the powerpack to the coil. It said the DVA voltage should be 150v ac. I don't have a DVA tester, just regular digital meter and the voltage was the same on all cyl @ .01v. I thought I read somewhere about multiplying by 1.414 and thought it applied to this, but I guess I either didn't do it correctly or I completely missed the mark on the test and need the DVA. I did check the spark again with the adjustable tester, all cyls. firing bright blue arcs. Is it possible to check the powerpack with just a regular meter? Anything else I can check without the special tools??

Anyway, thanks for the input. It's very easy to get discouraged by these sorts of problems but I'm still trying hard to think of it as a challenge that I will win!

 

[Dennisanoka]

Re: Stator/Timing base condition question, re. rough idle

When I read your post it seems as though you have not verified the spark sequence is in fact correct. I read uncertainity and then you move on to other possiblities. One should not move on until you can check a potential issue off the list. Secondly, you must try to troubleshoot this when it is malfunctioning. So let's suppose the sequence is correct, btw do you have a manual to be sure wires to and from the coils and to the plugs have not been swapped?
So if the sequence is correct: when it is malfunctioning you must determine what cylinders are not firing, most easy done by pulling a plug wire and listening for a change. NO change- that's the one. Then go thru the rest and see if the others all make a difference when you pull them.

 

[Mickyfinn]

Re: Stator/Timing base condition question, re. rough idle

Hi,

Thanks for sticking with me and making me do it right! No, I have not confirmed that the sequence is right. I have a Seloc manual that doesn't often match my motor it seems. I haven't purchased a real one yet (please recommend a vendor if you know one). My only thought on the sequence, as with some of the other potential problems, comes back to it only being an idle issue and especially one that happens only intermittantly. Certainly correct me if I'm wrong, but wouldn't the wrong sequence cause problems constantly and throughout the throttle range? It truly purrs just like it's supposed to quite often, I'd say @ 40% of the time. The problem seems to turn on and off like a switch has been thrown, which makes me think it's electrical in nature. When it does go bad though, it acts like the sequence could be off, pauses, sneezes, drops rpm, stalls etc. I haven't been able to pull plug wires on the water because I hate reaching around the back of the motor from the boat, but I've tried to isolate it by pulling wires with the muffs on and haven't had much success telling which is the bad cylinder. It seems to be more like a quick misfire than actually dropping out for any length of time. That was one of the first tests I read here, and did a few months ago. I couldn't isolate it so I thought I'd start with the fuel side of the potential list of problems. I still haven't ruled fuel out completely, but there's not too much more to check still. I'm thinking of pulling it apart to check for trouble behind the air silencer base; manifold gaskets and reeds (unless you think I'm wasting my time...). I'm not exactly sure what I should be looking for with the reeds, in fact, not even really sure what they do. I'd love an education if anyone's willing.

As for the firing sequence though, I'll try to check that out again too. If I remember right, it seemed that the colors in the Seloc didn't match the wire colors leading to the coils. If anyone knows, or can point me to somewhere I can find it out, that would be great. Also, just to make sure I've got it right, #1 cyl is top starboard (top right if looking at it from behind), #3 is beneath it, #2 is top port with #4 lower port. Right?

Thanks,
Evan

 

[Dennisanoka]

Re: Stator/Timing base condition question, re. rough idle

When you say you could not tell which cylinder was acting up when you were on the muffs, was the issue happening when you did the test? Secondly, even a healthy engine will change when you pull just one plug wire so no matter what, you should have noticed something change. So when you have it on the muffs or in the water and it is acting up, let it act up for a a while and then pull each plug to see if there is any visible difference between them. Or pull each plug wire one at a time, if three make a change and one does not you have isolated it. If the issue can not be isolated to any one or two cylinders then the issue is caused by something common to all.

 

[Mickyfinn]

Re: Stator/Timing base condition question, re. rough idle

Hi,

Sorry, should have made that clearer. I did notice the change when each plug wire was pulled, I just couldn't identify one cylinder that was different from the others.

I'm going to try to get to those reed boxes this afternoon, maybe something will turn up there.

Thanks,
Evan

 

[Dennisanoka]

Re: Stator/Timing base condition question, re. rough idle

I'd save my time. I highly doubt you'll find anything there, considering the effort involved. I can't remember where all the bolts are but you may not be able to get to them anyway. When it is acting up andf you pull out the plugs do they all look the same?