OMC 58L Cobra running VERY rough

"ok, so I had a slight "po

"ok, so I had a slight "popping" sound through the carb, so I changed, cap/rotor and fuel filter. Basically ran the same, maybe slight improvement(less popping). Then things went wrong... saturday I took the boat out, was normal running. anchored for a bit, then I had to do an emergency start and go - FAST (drowning victim nearby). After I got them out of the water, went to start the boat and didnt want to go.(thank god was after I got them). When it did finally start its really rough, like running with a few cyclinders down. the motor shakes violently if you try and idle it, has no power.

I was told leaking manifolds/risers? I been reading posts here and learned of this interrupt switch - could I have done something with the quick start and go?

any suggestions?"

"Mark,
It sounds like it was

"Mark,
It sounds like it was either running with the timing to far advanced or it was lean. Both can cause the sound you heard. Poor fuel can be part of it.
Could also be a bad distributor cap.
Can be alot of things.
At this point check the compression and timing. Read the plugs to see how they were burning. Check the cap & rotor & ground connections.
See how that turns out before you do anything else.
Is the rpm under max rpm for the engine?
I doubt the interupt switch has anything to do with this."

"see I thought of the timing,

"see I thought of the timing, water in the gas(full tank) and running lean. But what boggles me is how fast it went from relatively normal running to this. it literally ran fine an hour previous. nothing happened, nobody touched the motor - except that I had to start and go FAST. After that it runs like crap.

I'll check everything mentioned of course.

thanks M"

The popping sound may have bee

The popping sound may have been one or more valve going bad (mushroom). Do a compression test. I am afraid the heads must down and one or more valves have to be changed.

"Update - I got off really luc

"Update - I got off really lucky!!! I had 3 dead cyclinders, hence the NO Power. The 3 spark plugs in question had their ends Blown off. It seams that motor with those manifolds are an absloute bugger to change and tighten those 3 plugs. So the last guy only did them finger tight. the plugs therefore bounced around, got loose and had weird detination. 3 hours later of changing those buggers, the problem is solved!!!

If anyone has a simillar problem, check the starboard side plugs 5,6,7 and see what they look like.

Thanks for everyone's 2 cents.
M"