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43 OMC Popping throught the carb

C

canucker

New member
"Wondering if anyone has had t

"Wondering if anyone has had this problem and if so what the fix may be? I have a 4.3 OMC that started intermittently popping through the carb last boating season. This seemed to only happen under load when trimming. This season the problem has progressed to the point where there is a constant popping after the engine has warmed at 3/4 to full throttle and I can make it pop at will by hitting the trim at pretty much any speed. I changed the plugs, cap and rotor but this made no difference. I am now thinking that I should change the ignition wire and coil and see if this helps. Does this make sense or am I just wasting more money?


Thanks."
 
"Hold it: It does this ONLY w

"Hold it: It does this ONLY when you trim th boat? If so, that's a voltage problem. THe distributor is not getting enough voltage.

Jeff"
 
"Agree with Jeff, sounds like

"Agree with Jeff, sounds like a bad connection somewhere. I would remove and clean all battery cables (both engine and battery end) and possibly on the assist solenoid too. Make sure they are all good and tight!"
 
"Not only when trimming but at

"Not only when trimming but at higher rpm's as well. My battery is on it's way out as it seems to lose a charge after sitting for longer periods of time. I kind of discounted this as the problem though as my thinking is that if it has the cranking power/voltage to start the engine it should have enough voltage to supply the ignition system. Am I out to lunch on this? Also, I have good tight connections on the battery as I did check this. This started as a very intermittent problem and now has progressed (probably over about 20 hours of use over the last 2 seasons) to something that is constant at high rpm's and when trimming. Makes me wondering if something is gradually breaking down? My voltmeter does dive quite a bit when hitting the trim button but I thought this is just normal considering the load.

Thanks"
 
"You need to check the other e

"You need to check the other ends of those cables and at the solenoid as those are the ones that get neglected (out of sight out of mind) still sounds like a voltage drop problem, with a good battery and high rpm's the alt should be putting out enough so that using the trim should hardly be noticeable on the guage."
 
I do not recall just when or w

I do not recall just when or what the cause was but someone else had a problem like this earlier this season. If you have the time it could be worth looking in some of the old postings and see if you can find it.

Have you ever change the filters or had the carb jets cleaned? It could be running lean at the higher rpm from dirty filters or jets that have the green grunge in them.
 
"I have this same problem. ba

"I have this same problem. backfire at WOT (full throttle). It usally only happens the first hour or so of boating, but sometimes all the time.

It only happens at full throttle, anything else and it's running great.

I've changed oil, outdrive oil, spark plugs, new dist cap, new electronic ignition, new shift module, fuel filter, and all new fuel.

I'm running premium fuel(93 OCT), could this be the problem?"
 
Change the fuel water seperato

Change the fuel water seperator and change/clean the small filter at the carb. Then retry
 
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