Simple Carb question,,,I hope!

OLJOCLARK

Cadet
Joined
Apr 5, 2010
Messages
27
Hello folks,,Cadet Clark here.Still tryin to figure out my stalling problem on my 1978 70 hp Johnson.I tried something I saw someone do once trying to check out carbs.I cupped my hand over each carb one at a time while running the motor on water ears.The top 2 stalled the motor down to stop, but with the bottom carb cupped off the motor would stay running.Any Ideas ? Thanks, in advance.OLJOCLARK
 

Daviet

Fleet Admiral
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Sep 24, 2008
Messages
8,958
Re: Simple Carb question,,,I hope!

How is the compression and spark on the bottom cylinder?
It may be time to overhaul the carb.
 

OLJOCLARK

Cadet
Joined
Apr 5, 2010
Messages
27
Re: Simple Carb question,,,I hope!

The compressions on all 3 are 110 .I'm soaking the carb tonight.I had already cleaned them several times and replaced needle valves and seats,Floats are good and level.thanks for your reply.Just wondering what I haven't done right.I know I haven't been able to get a wire in to all three small holes yet. Gonna try that tommorow after work.I haven"t soaked them until now. Thanks
 

OLJOCLARK

Cadet
Joined
Apr 5, 2010
Messages
27
Re: Simple Carb question,,,I hope!

Oh yeah,,I've got a spark tester and I'm getting great spark on all 3 with about 7/16 gap a strong looking spark.Is it possible to have too small gap on the plugs?
 

OLJOCLARK

Cadet
Joined
Apr 5, 2010
Messages
27
Re: Simple Carb question,,,I hope!

Update. I found the inner round gasket in the bottom carb to be cracked.I replaced it and cleaned carb again.Now I get get the same response from all 3 carbs.Gonna give it a try in a few days on the water. I'll update then. Oljoclark
 

OLJOCLARK

Cadet
Joined
Apr 5, 2010
Messages
27
Re: Simple Carb question,,,I hope!

Oljo here again.Still no better! Today I decided to take the coil wires loose and Ohm em.2 coils read right at 2 ohms,1 coil reads .963 and is leaking the black stuff.I'll be trying a new coil next and will post the results.
 

Rscardina

Chief Petty Officer
Joined
May 3, 2010
Messages
513
Re: Simple Carb question,,,I hope!

any coil leaking anything isnt good,,, replace it..

if thats all you found on the carb side then a coils is first and see what she does.

Good luck
 

OLJOCLARK

Cadet
Joined
Apr 5, 2010
Messages
27
Re: Simple Carb question,,,I hope!

Thanks.I ordered the coil yesterday.It'll probably be friday or saturday before I can run it.That is if the part comes in as quick as it usually does from Iboats.I'll post as soon as I know something.I like to see a good ending on these post's.Maybe we'll have one this time.OLJOCLARK
 

OLJOCLARK

Cadet
Joined
Apr 5, 2010
Messages
27
Re: Simple Carb question,,,I hope!

OK! For anyone keeping up with this story,still no better.I probably needed the coil anyway but still not the answer.This week I pulled the exhaust manifold covers and found the inner gasket to be bad.Water sitting inside the exhaust port on the middle cylinder.I've ordered the gaskets.I broke off 3 cover bolts in the process soI've got plenty to do until the parts arrive! I'll post the results in about a week,I hope I've found the gremlin this time.Wish me luck.,,,,Oljo from Alabam
 

OLJOCLARK

Cadet
Joined
Apr 5, 2010
Messages
27
Re: Simple Carb question,,,I hope!

Yesterday I proceeded to drill and try to extract the 3 broken bolts in the block. No luck these things aren't moving.I was trying to turn one out and the block cracked!End of story,Parts motor for sale! Oljoclark
 

OLJOCLARK

Cadet
Joined
Apr 5, 2010
Messages
27
Re: Simple Carb question,,,I hope!

Yesterday I proceeded to drill and try to extract the broken bolts in the block.Not coming right out. As I was trying to turn one out the block cracked!.Parts motor for sale!I'm sure I had finally found my gremlin.Gonna move over to the Mercury forums for my next project.You dont know a good welder do you? Oljo out
 

patrick4266

Chief Petty Officer
Joined
Nov 29, 2007
Messages
591
Re: Simple Carb question,,,I hope!

Sorry to hear you messed up your motor but maybe it can still be fixed.
 
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