140 82 johnson

[donnym]

I have a rebuilt 140 1982 Johnson that has 120+ compression on all cylinders and is firing on all spark plugs. After it runs for a couple minutes it starts to bog down and then quits. After pulling all the plugs the bottom left has a bluish grey film on it and is clean, the rest show normal rich condition because I was told to run the first tank of gas at 25:1.
What could be causing this condition in that lower left ( port ) cylinder?
Could the jets on that carb be out of wack.
Could there be some way that water is leaking in there even though it shows great compression?
thnks donnym
fresh gas and new container of 2 stroke oil were used

 

[Sherman]

Re: 140 82 johnson

Try switching the coils on the two left cylinders. I suspect a weak coil. The clean plug sounds like it is just being washed with fuel. Make sure all cylinders will pass the 7/16 spark gap test. Resistence goes up as the engine warms. You might try the hair dryer on that coil to see if it breaks down with additional heat. This does not sound like water to me nor do I think it can be carb related since that lower carb also feeds the lower cylinder on the other side. Dying after a couple of min. sounds like you may have air leaking into the gas line.

 

[donnym]

Re: 140 82 johnson

Thanks alot for that info .
It certainly makes sense about the lower carb doing both lower cylinders.
I only get to work on it on weekends but will try that next weekend.
donnym

 

[emdsapmgr]

Re: 140 82 johnson

The blue/grey film could be trace amounts of water. You may have a blown headgasket or exhaust gasket. Did you retorque the heads and exhaust cover after a few hours of running? Any water intrusion tends to affect the lowest cylinder in the block. I have even seen cracked inner exhaust housings as well as casting holes (porosity) in the inner exhaust housings. Both can leak water into the lower cyl.

 

[donnym]

Re: 140 82 johnson

I purchase the motor several years ago freshly rebuilt and just got around to using it. It hasn't ran more than 30 mins total time. I'm going to check the coils first, since they are over 25 years old. Thanks for the additional info .
donnym

 

[donnym]

Re: 140 82 johnson

Well I switched out the coils, she fired right up idled at high let it settledown into a nice steady idle , within two minutes it started to miss by three minutes it stalled pulled the plugs the lower left was clean and had trace amounts of moisture. Other than retorquing the head bolts what else should I do? Can the inner exhaust housing be accessed by removing the outer exhaust covers? Any suggestions are appreciated
donnym

 

[cdoliver]

Re: 140 82 johnson

Re-torque the head bolts...not too much, remember this is alluminum. If the water intrusion hasn't stopped, you can change the head gasket easily. The head gasket is probably letting the water in. You will see exactly how it works when you get the head off.

 

[ezeke]

Re: 140 82 johnson

"It certainly makes sense about the lower carb doing both lower cylinders........."

No. Unless the intake manifold has been customized, each side of your two barreled carburetors feeds only one cylinder and has its own jets.

It is normal practice to re-torque head bolts after a rebuild break-in. If it wasn't done, do it now. Don't guess, use a torque wrench; 18-20 ft lbs.

 

[emdsapmgr]

Re: 140 82 johnson

Retorque the heads first. Second, if it still is a problem, replace the head gasket on the bad side. Go into the exhaust covers if the first two steps don't fix it. (these exhaust covers should also be retorqed after a few hours)

 

[donnym]

Re: 140 82 johnson

I had already purchased a set of head gaskets a couple of weeks ago because I was sure it was moisture on the plug when I pulled it out.
I got all new coils because it is a 25+ year old motor. Next weekend I will re-torque the heads and try it one more time. If it is still the same then I will pull the head off. ( I am only telling you what I will be doing so that you guys can interject with any other info) thanks so much for your interest and considerations.
donnym

 

[donnym]

Re: 140 82 johnson

Ok so i retorqued the head bolts.....same problem.
I removed the left head and the bottom cylinder is filled with watery greyish blue and is clean the top cylinder looks typical with black carbon for running on a 25:1 break in mixture. The fellow I bought the motor from certainly didn't lie to me about the rebuild ( brand new 30 over pistons and the block is marked
.030 on the cylinders, brand new head gasket with no indication of leaking or that the metal ring is blown or anything)
so................ what now?
Buddy a few posts back said that the exhaust gaskets can leak or something.
Suggestions? Do I now remove the center exhaust housing , how deep do I go?
thnx
donnym

 

[emdsapmgr]

Re: 140 82 johnson

The inner exhaust manifold could be leaking. Remove the (19 or so) bolts holding the outer manifold and you should be able to remove it, plus the inner manifold. You will need two gaskets: 323469 and 317955. You can get a water leak around the inner housing if the bolts were not torqued/retorqued properly originally or if the inner gasket failed. Check the gaskets for water markings. I have also seen casting porosity (holes) in the inner manifold which will permit water to enter the exhaust chest, so closely examine the inner exhaust manifold. Removal of the exhaust manifolds is not difficult. You don't need to get into the powerhead. Use OMC gasket sealing compound and torque to 60-84 in lbs. If you were ever thinking of working on the thermostat housing, this would be the time-once the exhaust system is off.

 

[donnym]

Re: 140 82 johnson

Thanks for the great info.
Going to do that today
donnym

 

[donnym]

Re: 140 82 johnson

Ok so I removed both the outer and inner exhaust manifolds and related gaskets they looked new and I could not see any sign of damage or were they could be leaking. I did notice that they were installed without any gasket sealer that my repair manual mentioned to use on both sides of both gaskets. Do you think that this could cause the water in the lower left cylinder?
I applied gasket sealer on both of the new gaskets I purchased today and re-installed the exhaust manifolds ( I certainly used every 3/8" socket , extensions and universals to do this re and re job!!)
I ran out of time so I didn't get a chance to try the motor again and figured it wise to let the gasket sealer set well.
My question is do you think that the sealant will do the trick and solve my problem? ( Certainly not holding you to your opinion if I find this repair doesn't work!!!! LOL)
donnym

 

[Dhadley]

Re: 140 82 johnson

Just keep your fingers crossed. If that doesn't do the trick the rebuilder needs to pressure check the powerhead for you. At least you'll be able to pin point the leak without putting more water inside a perfectly good motor.

 

[emdsapmgr]

Re: 140 82 johnson

Hopefully, your latest efforts will take care of the problem. Gasket sealer will also take care of surfaces that are not perfectly flat. I'd retorque after you go out once, as they may loosen once the block heats up. Keep us posted on your findings.

 

[donnym]

Re: 140 82 johnson

Well it won't be till next weekend when I get the chance to check it. Thanks for all the help. I will update this thread with what I find. When you say to pressure check it does that mean to pressurize the water manifold and see where the water is leaking?
donnym

 

[Dhadley]

Re: 140 82 johnson

Yep, the powerhead will have to be off but they'll block off the water passages and pressurize the cooling system.

 

[donnym]

Re: 140 82 johnson

Sorry for the long delay on this repair of my 140!
I finally found a guy that knows what he is doing and he replaced the base gasket and now the motor is running well. He said whoever had rebuilt had used the wrong base gasket and it was letting water in.
Finally! Thanks for all the opinions, ideas and help