Gun the engine to get idle down at start

[atomb]

I have a 96 3.0 lx mercruiser that at startup needs to be gunned a little -i kinda bring the rpms to about 1700 1800 to get the idle to fall to the 700 rpm range - what causes me to have to do this - Its a very new rebuilt carb -professionally serviced -Thanks for any input-this is all happening while the boat is in the water

 

[WizeOne]

Re: Gun the engine to get idle down at start

Even on warm starts?

 

[Fishermark]

Re: Gun the engine to get idle down at start

Perfectly normal with a carb / choke combination.

 

[lowkee]

Re: Gun the engine to get idle down at start

I'm not entirely sure if you mean it will stall if you don't or if it idles high until you do that. If it idles high maybe the throttle linkage or choke plate is sticking a bit. Just spray the hinge points with some PB blaster and try again. If it stalls unless you do that, maybe the choke is staying on too long or is it running a bit lean (back of the fuel mixture screw a 1/4-1/2 turn). Running lean can also make it idle a but faster than normal when cold, so that may be the same issue if it idles too high (but only if it doesn't idle high when warm).

With carbs, the rules tend to change by engine and carb setup, but those are my general tips. Let us know how it goes and what fixes it.

 

[atomb]

Re: Gun the engine to get idle down at start

on warm starts it seems to be 50/50. I'm thinking the mixture might be off a little -Ill probably play around with the mixture and see if i can do better than the current setup. Ill let you guys know what works out. No stalling.

 

[Fishermark]

Re: Gun the engine to get idle down at start

Ill probably play around with the mixture and see if i can do better than the current setup.

If it is just a fast idle issue at start up - that goes away with a little gunning of the throttle - then I think you are chasing after ghosts. Any "playing with the mixture" will probably do more harm than good. I say best leave well enough alone. But that's just me.

 

[atomb]

Re: Gun the engine to get idle down at start

thanks -Your probably right -best left well enough alone-Thanks for the good advice