got her all rewired, and now she runs, but backfires and dies

[Ranger 330V]

okay, 1978 140hp Johnson. Has been sitting for a couple years...have been oiling cylinders and turning by hand for about a week with two cycle johnnyrude oil. Today redid wiring, I now have fire all the way around. Mixed a pretty thick mix of oil/gas...two gallons and 10oz of oil...rather be REALLY smoky than sorry for an engine that has sat for a good while... Checked compression, 115 to 123 all the way around. Found TDC and number 1 is at TDC on the flywheel. powerpacks are wired A and B to the correct coils. Trys to start will hit a few revolutions then backfires and dies or just dies...really rough like one cylinder is firing at the wrong time. Then I tried idling up a little, a couple of times it hit took off and sounded great, but would act like it wanted to run away so I killed it. I'm thinking a timing issue but I don't know. Has anyone every seen something like this?? I have a manual but have not received my piston stop and timing light yet and I don't have my friends multimeter will try to get it tommorrow. I do have the DVA adaptor though. I've done what the manual says in the timing section except using the timing light to set timing as I don't have it yet. As soon as I get it I will try to see if number one is actually firing where it is supposed to. can a timing base malfunction and cause something like this?? the engine has been rebuilt, can the timing base be put on in a way that it would be off?? like stabbing a distributor one tooth off?? Ask questions away and I'll answer the best I can...Heck I'm really excited that the compression checked out and I have good blue spark on all plugs...not bad for 500 bucks for boat motor and trailer...well I wouldn't call what this thing was on a boat...more like a piece of fiberglass with a steering wheel. Thanks again!!

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

just read another post...about discribing the backfire...I haven't seen a flame or anything from the exhaust, alothough a good pop out of it, and water being flung out of the prop. I am wondering about the key under the flywheel now...maybe thats sheared. Going to check my wiring again...I did it once but i want to recheck...hate to miss something basic.

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

everything seems to be in order...going to get a flywheel puller monday...I read that a harmonic balancer puller with 1/4 grade 8 bolts works?? is this true? Any other ideas about the problem? Thanks!

 

[bgbass.1]

Re: got her all rewired, and now she runs, but backfires and dies

if your wires are not crossed at coil i would check that flywheel key could be sheared off and yes the puller and bolt are right i like to use a grade 8 bolt less chance of breaking

 

[tashasdaddy]

Re: got her all rewired, and now she runs, but backfires and dies

i think the 140 uses the 5/16 grade 8 bolts. there are different sizes for different HP.

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

okay, got the flywheel off...no problems...keyway there and intact, in great shape....visual inspection of timer base and stator are good. Everything looks to be fine. What else could be causing it to fire out of time?? Inside of the timer base was quit dirty as was the rest...well dirtier than you would like...going to make sure everything is as clean enough to eat off of and check my wiring one more time to make sure everything is right and look at instulation under the wrap on the stator and timer base...is there anything else that would cause this?? I've never read of something actually going bad and firing at the wrong time..I don't see how that is possible...flywheel looks fine...all magnets there and none are messed up or damaged...I'm at a lose here...hope someone can shed some light...thanks!

 

[HighTrim]

Re: got her all rewired, and now she runs, but backfires and dies

What plugs are you running? Are they torqued down to spec?

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

77JC4 champion plugs..I have fire on all of the plugs....just firing at the wrong time..I get a good backfire that shuts the engine off...something is off, I even tried starting it with a plug wire off and it wouldn't stay running..tried this on all cylinders...I'm going to check wiring again and clean and lub and put back together and see what happens...keyway was fine...thanks for the quick response!

 

[HighTrim]

Re: got her all rewired, and now she runs, but backfires and dies

Those plugs are good, and torqed down I hope? Assuming the fuel system and carb are ok, the main suspect on a misfire is usually the plugs. Boot or the inner terminal damaged or corroded. Have you looked in the boot? Faulty or crossed plug leads. Under torqued plugs. Or defective plugs. After that the ignition system is likely to blame. Timing off number 1, loose wiring, damaged coils, arcing around ignition coils, loose connections to coils or power pack, leads grounding out on any of the coils or key switch, arcing in key switch, then finally bad PP, charge coil or sensor coil.

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

have not done the whole ignitions test yet because its backfiring so bad...its just like a plug wire is switched...I've checked and rechecked...just checked everything against the wiring diagram and it all checks out...just finished cleaning everything very well, fixing to put the flywheel back on and try it out...so far everything checks out. I'm going to go through and check everything with the fluke one day this week. a dead plug, no fire, inconsistent fire I could handle and understand. but this backfiring and dieing I don't get. everything lines up, wiring looks good...all plugs firing...key is fine...magnets are fine...nothing visually looks bad....gone over alot of the insulation with electrical tape then 3M scotchcoat...can something else cause the firing at the wrong time?? doens't make sense...has to be a timing thing...I'll post again in a bit and tell you if anything changed after a good cleaning and putting back together. thanks

 

[HighTrim]

Re: got her all rewired, and now she runs, but backfires and dies

you were going over the leads for the plugs with electrical tape? Were they damaged? If so , replace them, no tape. Did you check the condition of the inner terminal like I said, that will give you a good indication of the condition of the rest of the plug wire. Pull a plug boot off and have a look, if it is corroded or damaged, cut the wire back, allowing enough to still reach the plug, trim off a bit of insulation, fold the wires over, put in a new inner terminal (you will need to buy plug boot kit), lube it then slide the new boot over top. But if the wires are as bad as you say, just get new plug wires. Crossed leads or faulty leads will cause the problems you describe.

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

plug wires are fine...one was mess up on the coil in and taped...I took that off...cut the damaged off and pushed back into the coil. I just got back from trying it...this is what happend...it continued to backfire and die...then I tried something...I knew last night if I idled it up it would run...well I unhooked the timing advance and worked it by hand and left the engine at idle speed...if I pushed the timing advance up it would run until engine vibration pushed it back down then it coughed and backfired and died...if I leave the timing advance all the way down the way it would be at idle it will back fire but if I pull it up towards max advace it runs very nicely. everything is put together right and wiring is fine. everything is torqued down. I still don't understand why it is doing this...it just doens't make sense to me...have you ever heard of such as this?? its like the timing base is on wrong...but its on just like the manual shows....as is the stator...almost like a distributor on an older vehicle that when you stab you get it one tooth off...but that can't be done with this...any ideas?? thanks!

 

[HighTrim]

Re: got her all rewired, and now she runs, but backfires and dies

I havent seen on your post whether you checked the spark or not? Did it jump a good 7/16 of an inch with a strong blue ZAP!! if you did? IF your wiring is good, the timing is on (which you are unsure of) you'll need to check that next. Engine performance depends on the accuracy of ignition timing and carb link n sync. If you replaced major power head components, or disturbed the timing pointer, the pointer should be re checked against the Top Dead Centre mark on the flywheel. To check it and adjust:

1. Disconnect the spark plug leads and remove plugs.

2. Temporarily set timing pointer mid way in its adjusting slot. There is a piston stop assembly tool that you can use in number 1 cylinder hole but there are other homemade tools you can use . Anyways, install the tool, or whatever, and turn the flywheel clockwise until the piston contacts the end of tool. Adjust the tool to the proper setting (as per your manual) and lock it.

3. Mark a line on rim of flywheel adjacent to timing pointer. Now turn flywheel counterclockwise until the piston contacts the tool. Mark a line on the rim of the flywheel opposite pointer.

4. Using a scale or tape measure, measure the mid point between the two lines. Mark the mid point line on the rim of the flywheel. If the mid point line and the cast in TDC mark on the flywheel are in agreement, the timing pointer alignment is correct. If not, turn the flywheel to align the mid point mark with pointer (hold flywheel in this position). Loosen pointer adjustment screw and move pointer to align with cast in TDC mark on flywheel. Tighten adjustment screw.

5 . Check timing with a timing light on spark plug wire number 1 as per the manual you have. Ill assume you have those directions in there, but if not just ask and someone will be able to help you out.

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

okay, the engine will run and well...if you keep the timing advanced by hand...when you do this though it will not idle down...with carbs in idle posistion, choke butterflies open, it runs high....I'm probably because of the advance, if you push the advance back down to idle posistion it backfires very hard and dies. I have checked TDC by using a rod on the piston and turning the flywheel until the rod stopped moving...know thats not right, but haven't gotten my piston stop in the mail yet. When I did this TDC lined up with pointer...I know that was not the right way to do it but I know and engine should at least run with the timing close...as soon as I get the piston stop in and my timing light I'm going to reset the timing...but that still will not fix the problem of it backfiring when the timer base is at the idle posistion...I'm just at a loss here...I have checked spark and it is good, nice and blue...compression between 115 and 123 on all cylinders...wiring is good...all cylinders are getting fuel..even if they weren't it wouldnt' backfire severely and die. If I'm missing something please tell me because I don't really know where to go from here...when you advance timing it runs when you put timing back into idle posistion it backfires harshly and dies. Thanks again...surely we can figure this out...lol. I haven't seen anything on here yet that hasn't been solved.

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

I guess I'll have to check the timing with the plugs removed because it won't idle...maybe that will tell me something. I thought about this earlier...what if I set timing and pointer, then check each of the spark plug wires against the flywheel...if I'm thinking right each wire should fire 90 degrees apart...which when you put the four together would give you the 360 degrees of the flywheel...is that correct or am I not thinking right...maybe that would tell me at least if I had one cylinder not firing at the right time...which I think its bigger than that...because when you advance the timing by hand it WILL run...and well and smoothly. when you put the timing in the idle posistion it back fires and dies. lol, seems like I can't ever be one of the lucky ones with a crossed plug wire or sheared key...lol.

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

bump..

 

[HighTrim]

Re: got her all rewired, and now she runs, but backfires and dies

what is your starting procedure? Are you referring to your fast idle lever?

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

no..this motor is on a stand, not on a boat...so everything is being done with muffs and no not the high idle lever...I'm not using the controls as to get it started I had to advance the timing lever...I found last night if I idled it up it would run...and as you idle it up it advances timing so I decided to try to advance timing without opening the carbs to see if it would run..and it did...ran like a top..but as soon as you push the timing lever back to the idle posistion...ie...push the high idle lever back down if it were hooked up, it backfires and dies...and I'm having to push the idle lever to nearly max advance to get it to run...if you go down I'd say below 15 degrees of timing it backfires and dies..I just got my piston stop today, so hopefully my new timing light will come in tommorrow and I'll see what the timing really is. this really concerns me because I know you can set the maximum timing...and by setting the idle you set the idle timing, but its not going to idle...I don't see how if the flywheel is in the right posistion..all wiring is good and in the proper place, I checked this four times with my manual that it would run so badly out of time...you can't put the trigger on wrong...theres only one way for it to go...I'm just bumfuzzled...soon as I get my timing tested I will post it...something about this just doesn't seem right...doesn't go along with anything I know...since it was rebuilt I wonder if someone has put the wrong trigger or stator on...is this possible?? all the parts look original as they are all the green parts...coils, stator, and trigger...one power pack is new...CDI..the other is an original...I'm going to replace all the ignition equipment with new CDI stuff later on...and use the old as spares but I would like to get what I've got working...just throwing parts at something is for the birds..thanks again...maybe we'll get this thing licked pretty soon...its really eating at me..lol.

 

[Ranger 330V]

Re: got her all rewired, and now she runs, but backfires and dies

bump

 

[iwombat]

Re: got her all rewired, and now she runs, but backfires and dies

I was about to suggest you do the static timing against #1 and make sure they're all 90 degrees apart. I see from a couple of posts above that you're off to do that next. I think that's where I'd go now.