Unusual Problem HELP

[Donnie Durbin]

1989 50hp Force was running on one cyl. Had blown head gasket. Sounds simple.
Replaced to specs and inspected while down. It is getting fire to both plugs and getting gas.
It will still only run on one cyl. Good compression on both.

 

[my1stboat1]

Re: Unusual Problem HELP

its not unusual... you lost spark to that cylinder prior to popping the head gasket... You need to check spark at that cylinder and then start diagnosing the problem to ur spark issue.. But most likely you lost spark to that cylinder and then the engine running only on 1 hurt the headgasket

 

[Donnie Durbin]

Re: Unusual Problem HELP

Nope. Still had spark and still have spark at both cyl. It is the top cyl that wont run. Even switched the coils., and still top cyl wont run.

 

[jerryjerry05]

Re: Unusual Problem HELP

What's compression?Need numbers for both.
Check reeds? ZProfile?J

 

[Donnie Durbin]

Re: Unusual Problem HELP

120s both.Reeds look good. Its getting gas in both cyl. When you take plugs out and turn over you can see and smell the gas.

 

[Donnie Durbin]

Re: Unusual Problem HELP

Anybody else?

 

[Frank Acampora]

Re: Unusual Problem HELP

If an engine has spark at the correct time, fuel, and air, It MUST start and run. No two ways about it. So now you need to determine what it is not getting.

Start by removing the plugs and testing ignition on a spark tester. If the spark will not jump a 1/4 to 1/2 inch gap, it most likely will not fire a plug under compression.

You don't say which cylinder does not run but the bottom generally runs a little richer. So check that both cylinders are getting enough gas to fire and one is not getting too much.

Check the fuel pump diaphragm--a pinhole has been known to wet foul only one plug.

 

[Donnie Durbin]

Re: Unusual Problem HELP

Diaphram has large hole. Ordered one. Will get back with results.

 

[Nordin]

Re: Unusual Problem HELP

Now you pointed out the problem. It is getting to rich mixture in the bottom cyl.

 

[Donnie Durbin]

Re: Unusual Problem HELP

No, runs great on the bottom, top just flooding out.

 

[essie]

Re: Unusual Problem HELP

Gentlemen feeling alone at sea. I also have this issue but it not the top cylinder it is the bottom cylinder. I have went as far as replacing the main controll (CDI) and still have the issue. 35 hp 1991 Force. I know I am getting good spark, compression. Could it be the reed values? Why I ask, is I found chunks of rubber from the prime balls and fuel line. Your help is greatly appreciated.

 

[Donnie Durbin]

Re: Unusual Problem HELP

Problem fixed with new head gasket and fuel pump diaphram