40hp will not fire

quackupp

Cadet
Joined
Jul 7, 2004
Messages
12
My 40 hp will turnover but will not fire...cleaned fuel tank, replaced fuel filter, replaced plugs but doesn't appear to
be getting gas to the carb. Also, not sure if plugs are sparking. how can I check both areas?
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,909
Re: 40hp will not fire

First things first, verify you have spark in the plugs. Buy an in-line spark tester from auto store or even at Walmart for dirt cheap and you should be able to verify if you have sparks or not. If you do, then it is time to troubleshoot fuel related problems. The best way to troubleshoot this is install a $5 clear fuel filter between the fuel pump and the carb input connection. Prime the fuel primer until the clear fuel filter is full and then try to ran the motor. If it won't ran still, you know the problem is in the carb. Make sure the carb's air-fuel mixture is set one turn out from slightly seated. Better yet, read one of the stickies (top posts of the forum) about link and synch to properly set your carbs.
 

gregmsr

Petty Officer 1st Class
Joined
Sep 20, 2006
Messages
391
Re: 40hp will not fire

Quick and dirty? Remove plugs, carefully pour in a little (spoonfulls) of gas mix into cylinders, replace plugs..and see if it will fire. Should hit a time or two, then go from there.
 

Big Fish Billy

Petty Officer 1st Class
Joined
Dec 31, 2009
Messages
301
Re: 40hp will not fire

And take a compression test while you're at it.......
 

quackupp

Cadet
Joined
Jul 7, 2004
Messages
12
Re: 40hp will not fire

Thanks for the info....I am getting spark to the plugs and I see gas in the clear fuel filter but doesn't seem to be going to carb? Also, not sure choke is working?
 

MickLovin

Master Chief Petty Officer
Joined
Feb 18, 2013
Messages
822
Re: 40hp will not fire

You may have a fuel diaphragm problem, Take the fuel line off the carb and crank it and see how much fuel is coming out. Also may help to check your float levels of your carbs and while your at it give them a clean. :)
It could be junk in your needle and seat.
 
Last edited:

gregmsr

Petty Officer 1st Class
Joined
Sep 20, 2006
Messages
391
Re: 40hp will not fire

Dump a little squirt of fuel in the cylinders then try...least it will make you feel little better if if fires once or twice. Heck, it might take off. Its happened to me before....
 
Top