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Help Mercury 40HP 2 cylinder 2 stroke carb issues

RyanEC

New member
Hi guys,

Need some assistance / advise on my 40HP Merc, 2 cylinder model, round about 1998 model.

Problem started with motor bogging down when at WOT but would idle correctly when pulling throttle back, soon as you want to accelerate again it would want to cut out but if you pull throttle back again it would then idle fine again. So I did the following:

1. Cleaned carburetor and replaced all gaskets with Quiksliver parts from the agents.

2. Rebuilt the fuel pump with Quiksliver parts from agents.

3. Check all hoses / fuel connectors from Tank to Engine for any leaks / wear, ended up just replacing the fuel line from pump to carb.

4. Replaced spark plugs.

Now my problem is, and I never noticed this before that when I primed it after re-installation fuel leaked out of the overflow and the one jet in the carb (Please see pics - red arrows pointing to where fuel is coming out). Did I prime it to hard and should fuel be leaking out even when "over" priming or do I have a float and needle issue too?

My other issue is that, it idles very high now. It did start up first time which is good I guess :) Why would it idle higher after the rebuild and how would I set the idle?

Thanks any input will be appreciated. Pics below:

Cheers
Ryan
South African boater
 

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Last edited:
Thanks Jeff appreciate - please explain what you mean by rebuild? As mentioned I replaced all gaskets, should I have replaced the needle valve and float also?

Thanks!
 
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