Black plugs all the time....

[kimchee]

Hi all, I have a 5.7L 8cyl 4bbl mercruiser 1996 (maxum 2300SC).

My toy suffers from a common problem which many are dealing with, which is most likely caused by a poor functioning carb... Which leaks fuels into the carb when I shut off the engine, causing a difficult start when warm...

I have overcome this hard start by following the advice of many on this board by starting at WOT, and easing back when started... However, at the risk of sounding ungratefull, I have noticed that my plugs are always black... Which I assume is due to the faulty carb OR WOT starting... What can I do to overcome this....

As I predict though, many of you will tell me to simply have the carb rebuilt.... huh... Thanks Everyone....

 

[Boomyal]

Re: Black plugs all the time....

You guessed it, send your carb out to a qualified rebuilder? Don't know what carb you have but they are not for the novice.

 

[Scaaty]

Re: Black plugs all the time....

Yep, do a reputable rebuild, then get back with the results

 

[DHPMARINE]

Re: Black plugs all the time....

Have you seen the fuel runing into the engine after shut down ? This would constitute a rich problem,but I also think it would burn off.And not show on the plugs.But if you've seen it,yes a rebuild is in order.

Black plugs might be closer related to a closed choke or a clogged flame arrestor.

DHP

 

[kimchee]

Re: Black plugs all the time....

hmm... Closed choke or clogged flame arrestor....

Well, is there any way to find out if my flame arrestor is clogged?? I clean it with carb cleaner everytime I remove it which is about once a month... So, I don't think that is the problem.... the flame arrestor that is....

Thanks anyways.... I will replace the carb.. and get back to everyone....

 

[Silvertip]

Re: Black plugs all the time....

Why replace the carb if all you might have is a malfunctioning or misadjusted choke? Porous carb castings caused leakdown when the engine is shut down but after being restarted, would not cause black sooty plugs. A bad choke would be the first thing to look at.

 

[Alumarine]

Re: Black plugs all the time....

Are you sure the plugs are the right ones?

They might be too cool.