Powerhorse Tuning Questions

[TerryOlson]

I just bought a new Powerhorse 208cc motor. It was damaged in shipping, originally sold through northern tool, returned, and ultimately sold through a discounter on ebay. The air cleaner housing was cracked and I got a pretty fair discount so I'm pleased with the purchase.

I see no mixture screws on the carburetor. I know it is set from the factory, but I'd like to lean it out just a hair because it sputters a bit on accelleration as you get toward the higher end of the RPM range. Not a huge deal, but I'd like to adjust it if I can.

I was certain the mixture screw was behind a brass plug on the side of the carb. I checked the google finding no exploded views of the carb and decided to remove the plug to access what I was sure was the jet. Instead, I found a series of tiny holes and it appears that this is one of the metering passages leading from the aircleaner end of the carb body. I don't know why there's a plug there - cleanout purposes maybe - but no jet or adjustment screw. I put it back in place humbled.

Anyway, can anyone steer me in the right direction?

As an aside - the engine really pulls nicely on the low end and it's very quiet compared to the old B&S it replaces. I really like the quality of parts - I'd expected something a little rougher in fit and finish but the engine seems pretty well built - save for the lack of carb adjustments.

I have yet to play with the governor and the throttle assembly is a bit funky, but a couple springs in the right places should resolve that. If not, I'll bypass the governor assembly and cap max throttle with a set screw to keep the kids from blowing it up.

Thanks in advance for any advice you can offer.

 

[Kenny_McCormic]

You have a POS emissions carb, be lucky it runs rich rather than lean.

 

[KieranM]

i wouldnt say its a brand name carb then, does it have a name like han jin or something alone those lines?

 

[TerryOlson]

Huay on the side - nothing on Google for them either.

 

[KieranM]

yea there probably just a mas production carb, if you post up a pic someone might recognise it as a copy of a named carb

 

[anderkart]

I'd like to lean it out just a hair because it sputters a bit on accelleration as you get toward the higher end of the RPM range.

I'd suggest getting it all warmed up first and then while riding at full speed for 5 seconds or longer, suddenly kill the engine, coast to a stop and remove the spark plug to confirm if its reading a rich or lean mixture. (lots of plug reading info here: http://www.google.com/search?source...lz=1T4GZAZ_enUS369US369&q=reading+spark+plugs

If you confirm you need to re-jet, remove the float bowl. You'll find an orifice inside that extends down into the bowl and draws in fuel, you'll most likely find your main jet screws into that.

 

[TerryOlson]

We had some cooler weather yesterday and the kart runs perfectly (well, the engine does, I still need to replace the throttle cable and axle sprocket). Maybe the cooler weather helped - or maybe it's a break-in thing.

 

[KieranM]

yea its possible that the weather was causing the fault, it happens on pocket bikes, when it gets warmer its reccomended to go a jet size higher, though im not sure if this applies to karts

 

[MTU4X4RY]

Larger jet on warmer day?

KieranM,
Are you sure that it is larger jet when it's warmer? I thought that with cold weather comes dense air, the more air the more fuel, just my line of thinking though

 

[KieranM]

yes you are right, sorry i was not thinking straight its a jet size lower when its hotter out side, thanks for catching that