Trusty engine no go!

[joegrgraham]

Hi all,
I’ve got a Trusty with a Briggs and Stratton ZZ engine.
Tried to start it today, and not a dickie-bird.
The mag’ has been rebuilt and there is a good spark at the plug. Fuel is getting through to the carb, but the plug is still dry after repeated cranking. I’m guessing that the carb isn’t doing what it should.
So my question is, where is the best place to start with regards to the carb?
Thanks,
Joe.

[charlie]

I would try a drop of fuel in the plug hole, replace plug and give it a swing see if it fires. Could be a blocked jet in the carb.

[vhgmcbuddy]

I’m with Charlie. I’ve been in this position quite a few times in the past and used this old trick with some success.
It bypasses the carb so it will tell you if you’re looking in the right place. It may even clear a jet with the draw from the cylinder when it fires.
Good look.

[joegrgraham]

Hi again,
Been through the carb, and tried it today, and she runs! (albeit with a lot of spitting and popping, plus a few flames!).
The problem now is it will only run on tick over and fully choked, increase the revs and/or open the choke and it dies.
Any ideas?
Thanks,
Joe.

[vhgmcbuddy]

Is the idle set screw to lean, gently seat it up till it stops and back out 1 and 1/2 turns. If it has adjustable main you could try opening it slightly to see if it has any effect. You could also check tappets especially inlet valve.

[charlie]

Is there much wear in the throttle spindle/carb, this could be allowing air in causing a weak mixture which you are compensating for by closing the choke to richen the mixture.

[vhgmcbuddy]

My bet is the valves need regrinding particularly the exhaust one.

[joegrgraham]

Thanks guys,
Had another go with it yesterday, adjusting the mixture screw achieved nothing, so I think Charlie might be onto something with wear in the carb.
Series1gem, the valves have already been done.
Not sure if replacement parts are available for this carb, so if anyone has a spare ZZ carb or complete engine lying around?……

[joegrgraham]

Been doing some more research, and have found a really good website http://www.outdoorpowerinfo.com
It’s a really good site with loads of step by step photo’s for rebuilding different B & S carbs. Also covers Kohler carbs so may be of interest to Wheelhorse owners too .Through the site, I’ve noticed a few bits and bobs that are wrong with my carb.
Ordered a rebuild kit, loads available in the US. 🙂

[pete0250]

Looks a great reference site, thanks for posting.

[charlie]

A trick i have heard of but not tried is to spray something like carb cleaner around the spindle bearing area when the engine is running, if there is excess wear it will draw the spray in and engine will pick up.

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