Still working on 1988 DT140

[biederboat]

I thought I'd post a new topic on this as it's hopefully narrowed down a bit. Thanks to all those who helped me and, yes, it does have fuel/water separator with a new filter. Here's where I'm at now:<br /><br />Motor basically starts "semi-okay" in the driveway. It idles at about 1100-1200 rpm with just cooling water hooked up (is this too high?). It does seem to "miss" more than it should, about every 2-3 seconds there a pretty good interruption to the idle. I double checked compression, still good, all spark plugs look like they're getting good oil and they all definitely have good spark (pulling the plug wire gives me a good zap!).<br /><br />The two "indicators" are 1) when I pull individual plug wires while running, only cyl #4 brings it to a stop. #1 and #3 slow it a bit, #2 doesn't seem to have any effect so maybe this one has a clogged jet? Could it be the air/fuel mixture screw alone that would cause this? I have them all set on about 1 1/4 turns out from closed, factory manual says 1 to 1 1/2 turns.<br /><br />Indicator #2 is that maybe the fuel pump is getting weak. After idling a while, the motor sometimes just quits and it seems like when I open the bowl screws only a bit of fuel runs out. Also, cyl. #4 being at the bottom would maybe have it get the most fuel (gravity feed?)? But when I pump the primer bulb, it's always full of fuel and I can squeeze it until it's firm and it doesn't help it idle any smoother or anything so maybe it's not an issue? If it were a fuel pump problem couldn't you temporaril bypass this by squeezing the primer bulb?<br /><br />Well, thanks again for any assistance.<br />Biederboat

 

[jim dozier]

Re: Still working on 1988 DT140

So cylinder #4 is doing OK, cylinders #1 and #3, are not well, and cylinder #2 is dead. Get a spark checker at an auto parts store and check the quality of spark on all cylinders starting with the dead #2. The "ouch" method of spark checking is, shall we say, inadequate. If you do have a strong regular spark on all cylinders the problem has to be fuel mixture or compression. You said I believe that compression was OK which leaves fuel mixture. Either a dirty carb (orifices are what count not the outside) or an air leak. If pumping the fuel bulb has no effect its probably not the fuel pump.<br /><br />Pull the air box off and try choking the bad cylinders one at a time by sticking 3 or 4 fingers into the carb throat while the engine is running. If it picks up a little you are running lean on that carb for some reason.

 

[biederboat]

Re: Still working on 1988 DT140

Well, here's an update:<br /><br />1. Didn't have a plug checker but they are new and I switched enough of them to ensure that the plugs were not the problem.<br />2. It's now #1 & 2 that appear weak/dead. #3 and #4 are definitely pulling their rpm. Now, what's funny is that both choking #1 and squirting fuel into the intake made rpm jump a bit, indicating that it's running lean, right? However, adjusting the screw in (making it more rich, right?) didn't have any noticeable affect, even to the point of screwing it all the way in. I guess this is telling me that orifices are plugged? I couldn't get a really good feel for how #2 was behaving, maybe somewhat the same and somewhat different, just not as dramatic of an effect.<br /><br />Well, any suggestions, does it look like I should tear into #1 and #2? One last piece of info, at times there was fuel running out the front of all the carbs, just every now and then it would puddle up and run down, I had the motor at a slight forward tilt.<br /><br />Thanks,<br />Biederboat

 

[jim dozier]

Re: Still working on 1988 DT140

I think you need to go back into those carbs. There is a current post on the Johnson/Evinrude forum called "cleaning carburator" by Copano that you should read. It is not uncommon and entirely possible that despite the fact that you have been into the carbs they still need work. You wouldn't be the first. <br /><br />Completely disassemble the carbs. Get the rebuild kit for each carb. Replace the float valve and set the float height according to spec. Clean ALL (that means every orifice) with spray carb cleaner AND (this is important) compressed air. Reset the idle air screw (which you have removed, cleaned, and reinserted) to the proper number of turns out from lightly seated. I believe you are correct that your carb idle screws meter air so that screwing them in enrichens (reduces the air) mixture. By now you should have a manual to confirm these things and give you the proper specs for adjustment. <br /><br />Reassemble with new gaskets. Replace the carb to manifold gasket. Check fuel lines, oil hoses, and all hose connectors for possible air leaks.<br /><br />Set the throttle and ignition timing linkage according to spec.<br /><br />My bet is this will cure your problem.

 

[Duckworth1]

Re: Still working on 1988 DT140

Originally posted by biederboat:<br /> I thought I'd post a new topic on this as it's hopefully narrowed down a bit. Thanks to all those who helped me and, yes, it does have fuel/water separator with a new filter. Here's where I'm at now:<br /><br />Motor basically starts "semi-okay" in the driveway. It idles at about 1100-1200 rpm with just cooling water hooked up (is this too high?). It does seem to "miss" more than it should, about every 2-3 seconds there a pretty good interruption to the idle. I double checked compression, still good, all spark plugs look like they're getting good oil and they all definitely have good spark (pulling the plug wire gives me a good zap!).<br /><br />The two "indicators" are 1) when I pull individual plug wires while running, only cyl #4 brings it to a stop. #1 and #3 slow it a bit, #2 doesn't seem to have any effect so maybe this one has a clogged jet? Could it be the air/fuel mixture screw alone that would cause this? I have them all set on about 1 1/4 turns out from closed, factory manual says 1 to 1 1/2 turns.<br /><br />Indicator #2 is that maybe the fuel pump is getting weak. After idling a while, the motor sometimes just quits and it seems like when I open the bowl screws only a bit of fuel runs out. Also, cyl. #4 being at the bottom would maybe have it get the most fuel (gravity feed?)? But when I pump the primer bulb, it's always full of fuel and I can squeeze it until it's firm and it doesn't help it idle any smoother or anything so maybe it's not an issue? If it were a fuel pump problem couldn't you temporaril bypass this by squeezing the primer bulb?<br /><br />Well, thanks again for any assistance.<br />Biederboat

 

[Duckworth1]

Re: Still working on 1988 DT140

Biederboat,<br /><br />Sorry, I messed up the post. Is this a Suzuki outboard? If so I had a similar problem with a 115hp Suzuki. I had it in the shop for over six months while a mechanic was trying to trouble shoot the problem. After dumping a lot of $$$ (almost 2 grand), it turned out to be small plactic tube that was broken in the effected carb. The mechanic was thinking and replacing parts as if it was an electrical problem. It turned out to be a $ 5.00 part and an hour of labor to finally fix the problem. I learned from this ordeal to take the motor to someone fimilar with Suzuki motors. They should have the right equipment to trouble shoot rather than replace parts and test.

 

[rodbolt]

Re: Still working on 1988 DT140

duckworth1<br /> that goes for all motors not just suzukis. dont price shop with techs and dealerships. but dont walk in blindly and fork over cash. as a contract tech if I go to the counter and tell them a CDI is bad and I draw it and the problem is not solved I bought the CDI. so far I have never bought one. the money contracting is nice but it requires a firm grasp of electronics,fuel systems,cooling sytems and power transmissions. I am currently or have been certified by many. however one of the first things to do for work prep is drag out the manual. Iboats is one of the few things I do mostly by memory. even for a simple alpha or bravo seal job I look over the manual to refresh myself

 

[biederboat]

Re: Still working on 1988 DT140

Somehow I just now got the notification on the new posts. Yes, a Suzuki. Too bad about the long bill, I am a fix it myself kind of guy. Not because I don't trust techs, it's a money saving issue. Funny he thought it was electrical, it seems to me as if at least 75% of all running problems inside the cowl are carb related. I can take apart my carbs and clean them in just over an hour. I also know how to do some testing (pulling plugs, etc.) to help determine which cylinder it it. Someday soon I hope to make all this knowledge obsolete when I finally get the Suzuki 4-stroke 140!<br /><br />Biederboat

 

[fridays]

Re: Still working on 1988 DT140

No money but lots of time apparently. When you pull wires and #4 kills the engine but others only affect it a little and #2 does nothing tells me that #4 is leading the others and you probably only have do a careful syncronization. Coming into the middle of this I am assuming you have already cleaned your carbs. If you haven't ..do it then get back to us. Also check your trigger coil outputs at cranking speed. Many 1987 and some 1988 models were low and would cause poor idle. If low, pop the flywheel and move the triggers as close as you can to the flywheel.