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If the visual insp under the valve cover looks ok, I'd do a compression check and give the plugs a good visual insp.

If it's an older Holly carb, may have a bad power valve (assuming they weren't replaced with the rebuild).
If primary power valve is blown, the idle mixture screws won't have any (or very little) effect.
Also, if your idle speed adj is set too high, like to compensate for a dead hole, you won't be using the idle circuit.
Vacuum leak is another possibility.

if its a dead mis use insulated wire pullers and remove plug wires from dist cap one at a time till you figure out which cyl. then ck compression there...

Flat tappet cam?

I am going to say yes it is a flat tappet cam, not totally sure on that, because we bought the engines used, they are Blue water series mercs, from a 94-96 sea ray. Not sure the year they started using rollers, havn't ask dad yet. HOWEVER, just did a compression test on the engine. Number 5 hole is dead. All the others tested out just fine. So pulling the valve cover now, hopefully showing me a broke push rod, a un-seated valve rather then a bent valve.


The carb is a stock rochester. Yeh yeh I know that alot of people dislike them and call them junk, however on a stock set up they work very well 95% of the time, hopefully the head issue is a reason that it isn't taking the adjustment.

John

94 - 96 it should still be flat tappet so I was thinking it may have wiped a cam lobe out. But if you have no compression in a hole then it is not a cam lobe. I've seen valve stems get hung up in the guides from corrosion.

Put compressed air in #5 and listen to where it is escaping. Make sure the piston is at TDC of the compression stroke and both valves are closed. Bring the pressue up slowly as it may turn the engine if you hit it too hard with compressed air.

Broken valve spring, exhaust side?

Just pulled the cover, and has a bent push rod, what would appear to be a hung valve, so I am going to assume it is bent. Going to wack the top of it with a hammer and see if it pops back up, other wise i guess I am pulling a head. Spring is just fine.


John jr

Well pulled the intake, head off. Turned out the valve was froze in the guide. Must have stuck last year when we pulled the boat. So not as big deal as a bent valve. Hopefully have the thing back together tom, then can try to address the carb issue.

John jr