Gone from "no spark" to "hard start poor idle"

Jadebaum

Recruit
Joined
Aug 1, 2012
Messages
3
Basic problem. 2007 Volvo Penta 4.3l 2 bbl engine (4.3GL-G) Cruising fine on the lake. Slowed for large boat, engine started idling rough then died. Would crank but not start. Got it out of the water and home. Going through these forums, I traced the no spark to the ignition coil. Spark from the coil was weak and intermittent at best. Most of the time no spark at all. I replaced the ignition coil tonight. Great spark and it started back up. Yay. 10 days of troubleshooting paid off. Oops, wrong, now it won't idle. If I give it a lot of gas it will start after a lot of cranking, rev up poorly, but as soon as I back off throttle it dies. So I have gone from "no spark" to "hard start poor idle".

What do I check now? I am dreading taking it to a mechanic. (PS. I have had the boat for 6 weeks. I've had it out maybe 6 times and it always ran great. It ran great the morning that it died!)

Spark plugs are new.
 

Fishin Magician

Petty Officer 2nd Class
Joined
Aug 7, 2012
Messages
123
Re: Gone from "no spark" to "hard start poor idle"

Basic problem. 2007 Volvo Penta 4.3l 2 bbl engine (4.3GL-G) Cruising fine on the lake. Slowed for large boat, engine started idling rough then died. Would crank but not start. Got it out of the water and home. Going through these forums, I traced the no spark to the ignition coil. Spark from the coil was weak and intermittent at best. Most of the time no spark at all. I replaced the ignition coil tonight. Great spark and it started back up. Yay. 10 days of troubleshooting paid off. Oops, wrong, now it won't idle. If I give it a lot of gas it will start after a lot of cranking, rev up poorly, but as soon as I back off throttle it dies. So I have gone from "no spark" to "hard start poor idle".


What do I check now? I am dreading taking it to a mechanic. (PS. I have had the boat for 6 weeks. I've had it out maybe 6 times and it always ran great. It ran great the morning that it died!)

Spark plugs are new.



Water / Fuel seperater "filter"...bet it is bad...cause for poor idle......then add "SeaFoam" to gas tank to dry fuel cell, pump and lines out..
hope thats it..good luck
FM
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Re: Gone from "no spark" to "hard start poor idle"

That sounds more like the carb is flooding the engine. If it starts with the throttle wide open and no pumping, then idles poorly unless the throttle stays open then I suspect the carb internals need some attention.

Is there a strong smell of fuel? Can you see fuel vapor in the carb after it dies? What do the spark plugs look like?

Pull the dipstick, is there a smell of fuel from the oil on it? Does the oil look dark brown or grey?
 

Jadebaum

Recruit
Joined
Aug 1, 2012
Messages
3
Re: Gone from "no spark" to "hard start poor idle"

Well, changed the fuel filter and added seafoam. No appreciable change.

I do smell gas, but none coming from the oil. If it is a carb problem, that's beyond my ability.

I am admitting defeat and taking to a mechanic this morning. I will post with their diagnosis.
 

Jadebaum

Recruit
Joined
Aug 1, 2012
Messages
3
Re: Gone from "no spark" to "hard start poor idle"

Mechanic diagnosed it as gummed up carb. $640 later I dropped the boat with a rebuilt carb in the water and it ran great. ONCE it started. AND at higher speeds. Still has a very poor idle, so much so that trailering the boat was an adventure.

So, I'm taking it back to have it adjusted. I never thought I would say this, but I would rather it idled well than run wide open great. Must be getting old.
 
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