Engine misses

"I have an 89 omc cobra 5.8l.

"I have an 89 omc cobra 5.8l. The engine misses at idle speeds and into cruise speeds after the engine has ran for an hour or so.The problem has been noticed the last few trips out on the water. I go to run home and the boat misses, once i am cruising it seems to go away but when i idle down it is real bad. If i let the engine cool it seems to dissapear. I have tried new fuel filters, esa module, unplugging esa module, plugs rotor and cap, plug wires...
Not fixed yet.
the carb is a new edelbrock marine and i am wondering if i need to put a phenolic spacer on the carb to cool it.
Also the engine has the omc electronic ignition in the distributer, i wwas wondering if that may be faulty, however i was led to beleive the electronic ignitio either worked or didn't.
any help is apperciated ."

"Coils rarely are a problem bu

"Coils rarely are a problem but when they do go bad, and they don't go out completely, they give symtoms similiar to what you describe."

"the coil is new and was not t

"the coil is new and was not the problem, i am leaning towards the omc ignition module.has anyone had problems with them?"

The module is the only thing I

The module is the only thing I could think of that might have those symtoms. Modules seem to just quit completely when they go bad but it could be erradic. Modules are also unpredictable in terms of longevity. One could last 10 years and the next one 6 months. Auto parts shops will often test them for free.

"You might also have plugs tha

"You might also have plugs that are too hot, or the carb is jetted too lean. Suggest you chop the throttle and kill the ignition when it does this, then pull a few plugs and read their colors: White? (see above. Tan or light brown? change out the module.

Jeff"

"Yes, Fastjeff. Ed should be r

"Yes, Fastjeff. Ed should be running a cold spark plug."

I talked to a mechanic at work

I talked to a mechanic at work and he figures i have a bad plug wire.I will have the boat out on the weekend with a new set of wires and see if it is a fix

It's easy to damage plug w

It's easy to damage plug wires when moving them. That's why it is advised to be thoughtful when pulling them off to replace distributor caps and spark plugs. The symtom of the misfire after an hour lead me away from the plug wires but any electrical component can have peculiar performance when flawed.

"I found that my plugs are fou

"I found that my plugs are fouled, propably from the old fuel(2 Years old) that was in my tank. Also the plugs are the wrong heat range.
Thanks for your help, Happy boating "

"took the boat out, new plugs

"took the boat out, new plugs and proper heat range, ran better than it ever has. Thanks for all your help.
happy boating"