82 70hp black oil out the prop exhaust

[ctgmopar]

Hello All,
I have an issue with my (new to me) 70hp. Carbs were just synchronized, new plugs, timing good, cables adjusted yet after running a few minutes on flush unit I get a pretty big puddle of thick black oil out the prop exhaust. Lower unit oil is golden brown & clean. Could this be carbon buildup in the cylinders from either not being winterized or running too rich prior to me getting this engine? or sitting for about 2 years prior to me owning it? It started to sputter & saw the smoke, then wouldn't start up right away, put in New plugs again, ended up soaked & black so changed plugs a 3rd time & am just waiting for this to drain before trying to restart the motor. It idles fine & sounds good until it fouls the plugs...p.s. even compression mid 140's & mixture it perfect 50:1. I am guessing engine was sitting awhile & maybe carbon build up is burning off...Any ideas?? thanks.

 

[Rick.]

Re: 82 70hp black oil out the prop exhaust

That black gunk is perfectly normal for a two stroke engine. It is unbrned oil/gas mix from the exhaust. They all get it. Sounds like with your plug problem your slow speed might be set too rich. I would certainly recommend a decarb. which can be found at the top of this forum in the Top Secret File. Best of luck. Rick.

 

[Vic.S]

Re: 82 70hp black oil out the prop exhaust

Read Oil leaking around lower unit, by IWombat on the Engine FAQs board

 

[ctgmopar]

Re: 82 70hp black oil out the prop exhaust

Thanks to both of you, will try decarb & check carb settings. Chris

 

[ctgmopar]

Re: 82 70hp black oil out the prop exhaust

ok, well carbs are perfect, it ran today idling perfect, then sputtered after a good 15 minutes, some more carbon sludge coming out at the prop. then it died & wouldn't restart. has great spark, plugs are now normal looking, yet when pulling out all three & cranking over the engine it's blowing out what looks to be more carbon from mostly the bottom cylinder...which I figure is from the other 2 leaking down. has fuel getting to plugs, great spark, yet won't even attempt to catch. It was decarbed yesterday, & now looks clean behind the carbs, can't see in the cylinder too well, but doesn't look horrible. How long should it take to get out all the carbon & anything else I could try or any other ideas? I am stumped now. Engine was running, but badly prior to all work, carbs rebuilt & set, trigger cleaned & free, huge spark on all, yet keeps blowing this crap out the prop.?????? thanks

 

[tashasdaddy]

Re: 82 70hp black oil out the prop exhaust

read this. http://forums.iboats.com/showthread.php?t=330129

 

[ctgmopar]

Re: 82 70hp black oil out the prop exhaust

Thanks, but already had bowls off & they're clean, fuel lines are good as well....any other ideas....chris

 

[Lion hunter]

Re: 82 70hp black oil out the prop exhaust

So is it running good now? I may be streching it here but if your carbs are good and you've done the decarb process, it may just need a good bath. I would lose the muffs (It sounds like your using them if you can see the black junk) and run it in a barrel or on the water. A little bit of carbon goes along way for making things dirty.

 

[ctgmopar]

Re: 82 70hp black oil out the prop exhaust

it's not running, it will not catch. I hate doing this, but when I threw a bit of starting fluid in it, floored it manually, manually started moving timing lever around, while cranking, it pops & sputters, it wants to go, but won't catch.

 

[ezeke]

Re: 82 70hp black oil out the prop exhaust

Check that the throttle plates are fully closed and synchronized when you have the control arm in the neutral position and the warm-up lever down.

Also, check that the timing is advancing when you raise your warm-up lever.

 

[Lion hunter]

Re: 82 70hp black oil out the prop exhaust

So you don't mess up your motor trying to fix it you need to quit with the starting fluid. Use fuel mix designed for your motor in a squirt bottle. And don't "floor it" or go over high idle if the motor is not in the lake in gear and pushing the boat. Motors will runaway with no load on them and the results are bad.

 

[ctgmopar]

Re: 82 70hp black oil out the prop exhaust

Yes, I know the start fluid is bad, only shot that in twice to see if I get any results. Carbs are synch'd/ closed & timing does advance when warm up lever is moved.

 

[ctgmopar]

Re: 82 70hp black oil out the prop exhaust

The black carbon has stopped now & seeing fuel on the spark plugs (normal amount), it just won't fire up. I even checked the piston movement with the timing marks & all looks ok, yet when I mess with the timing arm when cranking that's when I get the "trying to start" reaction from the motor. I didn't think the trigger could be installed wrong due to the way it mounts to the engine. Any other ideas? I am all out at this point.

 

[Lion hunter]

Re: 82 70hp black oil out the prop exhaust

So you don't run in circles you need to trouble shoot in order.

1. Check compression and report the results

2. Check for spark. A spark tester is best (a few dollars at auto parts store) Make sure you get a good hot spark that will jump 7/16". At that time make sure that all the wires are routed to the correct plugs. Might not hurt to run through the timing procedure 1 more time.

3. Fuel Which I imagine you have since it is on the plugs.

Once you have these answers we can go from there.

 

[ctgmopar]

Re: 82 70hp black oil out the prop exhaust

ok Lieutenant, here's the list:
1. compression good 143,143,138
2. spark (with tester) jumps a good 1/2 inch, nice & strong on all 3 cyl.
3. Yes have perfect mix of 50:1, 89 octane.
4. took fuel pump apart, was clean & working.
5. took off flywheel since timing arm was stiff, found a bit of corrosion, cleaned it up, & reinstalled, (moving nice & free now).
6. new plugs 32 gapped.
7. synch'd carbs, throttle plate closed on all 3. even movement on all 3.
8. plugs got covered in black carbon when it ran.
9. decarbed, got all black junk cleared, replaced plugs with new again.
10. started engine, ran 30 minutes, sputtered & wouldn't restart.
11. good fuel pumping into all 3 carbs (have clear fuel lines on purpose).
12. revisited steps 1,2,3, also checked fuel line, gas tank, connections all good.
13. checked timing by hand turning engine til piston 1 is at top, marked engine, turned the second revolution to piston stop on 1 & marked again, within normal limits.

What's next guys????

 

[Lion hunter]

Re: 82 70hp black oil out the prop exhaust

I think at this point I would put some fuel mix in a bottle and spray some in the cylinders and see if it fires. Were the carbs rebuilt? If it fires that would tell me that there is not enough fuel getting to the cylinders to compress and fire. If it does not fire I would assume that sometime is wrong with the timing.

By the way that was a perfect example of trouble shooting. I may not have the answer but with excellent info like you provided someone will be along soon that may know better than me.

 

[Fisherball]

Re: 82 70hp black oil out the prop exhaust

Use WD-40 if you need a starting fluid. It's all lubricant that burns.

 

[ctgmopar]

Re: 82 70hp black oil out the prop exhaust

Thanks Lion & Fish....I trouble shoot pc's & networks for a liviing, also rebuilt car engines, logic is the same, track your steps....I appreciate the comment. I keep coming back to timing as well even though it seems ok. Sounds like an old car with the distributor in 180 off, but didn't think what was possible with this setup. I will try to wd-40 when needed, also will try the spray mix, but I think it's time to take flywheel off again & start over.

 

[ctgmopar]

Re: 82 70hp black oil out the prop exhaust

Ok, everyone that has responded to this posting issue. I have FOUND the issue & engine is running perfectly now. Here's the deal. It WAS an issue with the timing, but not what you would expect. When I pulled the flywheel & found that the key in the flywheel was sheered off. Don't ask me how, my only guess is that I used the old key after pulling it off the first time. I replaced the key with a new one & low & behold the engine came to life. Running very strong & right on the money with all the carbs. Hope this helps someone else that has an issue where the engine sounds like a car with the distributor in backwards. Thanks again to all who replied.. Chris

 

[Rick.]

Re: 82 70hp black oil out the prop exhaust

That's great news Chris. Glad you were successful. Flywheel nuts need to be torqued, not just tightened. Rick.