hblair

I'll check it all out again this afternoon or in the morning.

hblair

Guys I'm at a loss. I took the distributor back apart and checked everything to do with the ground. It all checks out good. Perfect continuity. I'm as convinced it's not ignitition as I was convinced it was the ignition a week ago.
How would I get a backfire out of the carb from ignition?

I plan to pull both valve covers, intake manifold, and really check out the valves rocker arms and especially the lifters. Heck I might pull the heads just to look at the valve seats.

I took my wife out and ran the boat some today at low rpm's and noticed the power is dropping even more. I hope I haven't hurt it by running it.

hblair

Symptoms:
Backfire and die at idle
Hard to start, (usually backfires thru carbs once or twice before starting)
Lack of power, only turns about 4K now
Found raw gas sitting in two front exhaust passages of right exhaust manifold

Things done/checked/replaced:
Swapped whole blower/carb assemblies
Replaced coil, cap, rotor, button with new parts
Swapped the whole distributor from other motor
Checked the ground on the distributor numerous times.

What gets me is the backfire thru the carbs. Do you guys know of a situation other than valvetrain issues that could cause this? (Other than ignition timing which is good)

I guess I'm going to check the compression and leak down on all cylinders next. (I did this on the right side already and the two front cylinders checked good but have raw gas in the passages??)

getrdunn

This is definitely a strange one. Like you said last post comp test amd leak down on all cylinders. Is it possible to swap out one harness plug at the engine to the other? Not saying to do this at all at the moment without thinking it through but... Kinda process of elimination if is somewhere in harness. Hold that thought for now.

SB

Very lean will cause this too.

502ss

Double, triple check the firing order and the plug wire locations. I know it sounds silly but worth a look!

getrdunn

That never sounds silly cause we all work long hours and can get agrivated with issues that keep us from doing what we love to do. Sometimes it is those things that are so basic that can be the ninja bug that drives us nuts. Even going back to confirm tdc. Did we address possible timing chain etc? Can't remember.

getrdunn

Correct but sounds like OP has raw gas in his exhaust. Yet with that said perhaps not firing on those cylinders. This isn't even my boat and it's driving me nuts.

hblair

Problem solved. I always preach to the guys here to check the simple stuff first. Always check fuses etc. first, then after the easy likely stuff checks out, then the complicated conpiracy theories.

Well, I bamboozled myself.. The #2 and #4 plug wires were crossed. I'm too happy to be embarrassed. Both sides are peppy and healthy now.

Thank you all for your time! Sorry it was something stupid. Thank you Jim for pointing out the obvious.

SB

You just proved your man hood ! Kudos.

Thanks for the follow up.

For others, when we suggest to check simple things like this, don't give us an attitude back, because schit happens !