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2006 4.3 L 190 hp hesitation on acceleration & difficult cool starting

G

Glen11

New member
I have a 2006 Mercruiser 4.3L 190 2 barrel carb. 30 hours on engine. I have 2 problems that may be related.
1. It does not start well when cool. It acts like it needs fuel. Pump accelerator does not help. It starts but takes a lot of cranking. The choke appears to be working.
2. Once started, the engine hesitates when given full throttle. Will accelerate in throttle is advanced slowly.
The accelerator pump does pump a healthy squirt on the first pump but the following pumps get much weaker. After 4 pumps the squirt is near zero. The same thing happens with the engine running (disconnected the linkage).
If you wait a long time 5+ minutes you can get another good squire from the accelerator pump but again only for 1 or 2 pumps.
When the engine is warm if you try to make a number of quick starts in a short time the engine will quit. If you space the starts out, it with not quit but you will have a hesitation.
So I am thinking plugged inlet to accelerator pump or bad pump But could their be a other fuel supply problem.
 
Re: 4.3 L 190 hp hesitation on acceleration & difficult cool starting

The accelerator pump well isn't designed for continual pumping; the refill slots are sized for a finite refill time.

Damn near every engine I've been around doesn't need a rich mixture to restart, if at operating temp. Try restarting it with the throttle half open. When it starts, pull the throttle back and let it 'fast idle' for a minute or two before going anywhere. many times a hot soak will supply enough heat to the fuel in the bowl to cause 'issues'; the fast idle period helps dissipate the heat, in various ways.
 
Re: 4.3 L 190 hp hesitation on acceleration & difficult cool starting

Glen, I am having the same problem on acceleration. When I try to accelerate quickly the engine will sputter for a few seconds prior to taking off and then runs fine. If you find anything out please let me know. I just started troubleshooting it last night.
 
Re: 4.3 L 190 hp hesitation on acceleration & difficult cool starting

carb rebuild, after checking the entire fuel system filters and don't forget the fuel pickup tube and anti-syphin valve. Check what psi the fuel pump is giving you. Check spark.

Want the post i made concerning rebuilding carbs just ask.

Want the post i made concerning how to run a boat with a carb just ask.
 
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