4 Wheeler Sputtering

A 15 year old 4 wheeler. Is it still the factory engine? How many hours running time would you estimate?

Therein may lie the answer.

Could be a vacuum leak or a clogged fuel filter. Too much air or not enough fuel to maintain the proper f/a ratio.

Doorman: Thanks for the "15 year old 4 wheeler" comment. My bad. The 4 wheeler is actually a 2005. 1995 is the year that I washed my socks. I get those dates confused. I'm guessing that I have about 200-250 hours on the engine which is original. I probably put 20-30 hours on it mud riding but in the last couple of years I've used it for pulling light trailer loads of stuff around my yard, and just easy riding. After it warms up it runs fine. It has no fuel filter. It came from the factory like that. I was thinking of a fuel problem but, as I said, after it warms up, it runs fine.

Only 5 years old, should have a lot of life left in her if she hasn't been worked hard.

You tell us two tanks of gas... these from a can of fresh gas? I assume (guess) this 4-wheeler is a 2 stroke; Is this an oil/gas premix?

I am hoping this is an easy fix for you. With money not spent on repair, maybe treat yourself to some new socks!

Actually, it's a 4 stroke. And, the gas has come from separate cans. I keep several 5 gallon cans handy for my mower, chainsaw, boat, generator, etc. I rotate the gas cans and I add Sta-Bil to each can. I haven't had any other issues with any of the other equipment. Someone suggested that I may have issues with the carburetor jet but I would think if that were the case the 4 wheeler would run bad all of the time. Guest said it may be a vacuum line. Seems more likely. I just wanted to get some ideas before I start tinkering. I'm no mechanic. I'm a parts changer. I hope it is not an expensive fix. I really could use some new socks. Thanks.

I'm leaning toward a vacuum leak. While it's cold and running rough, take a can of carb cleaner with the little red hose attached and spray around the carb and hoses and see if it makes a difference in how it runs, this may help you isolate the problem.

Good luck on the socks. I went to Walmart about 3 weeks ago and bought a weeks worth of socks and underwear for the first time in about 8 years, at my wife's insistence. It's pretty easy.

Experienced similar issue with a Honda thirty years ago, fix was applying fingernail polish to the tiny hole in the carburetors diaphragm.

I'll check it out.

Some Jap carburetors have an electric-heated wax-pellet diaphragm-driven idle air feed. Sounds complicated, and it is. I would look for something similar, since full engine heat makes it run right, when the whole carb is warm. Here's a very good illustrated page of disassembly, etc for the Keihin 32CVK which is listed for the 2005 376cc engine. http://myural.com/keihin_32cvk_disassembly.htm

Has the feul tank got a drain plug...if so, let the car stand a while, drain some feul into a clean holder to see if there is water and dirt in the petrol. Put one or two cups of methelated spiritus [and a cup of engine oil] in a tank full of petrol. 500ml brake fluid will also do the job. Fit new feul filters.

Now remove carburettor, write down exactly hou many turns the idling mixture scew can turn inwards carefully so that you can reset it after removal].strip and clean, blow out with compressed air. Be carefull of balls or pins dropping out if you turn the carburettor over.

There might be dirt or water in the idling jet.

jurie

As guest said it sounds like too much air. This can be caused by simple things such as a rotten vacuum hose, a clean and DRY foam filter ( it should be lightly oiled ), a loose carburetor or a broken gasket. If it is two stroke the seals around the output shaft and the kick start may be old and dry or even broken allowing air into the crankcase ( where the combustion mixture goes on its way to the cylinder).

Best of luck

Something also not suggested is a gummed up carb. Something that can easily happen over a few off seasons when its laid up with old fuel. Gummed up jets WILL lean the mixture out and if its bad enough make it look like a vacuum leak. And an engine thats at full operating temp is when it would be most tollerant of that excessively lean mixture.

I'd mix a half a can of BG44K in a 5 gallon fuel can of gas for that quad. and put the rest in your car to help clean up that fuel system. Its the only stuff I've found that really works as advertised.

If you have a Mikuni carb on there it's probably time for a rebuild. You can buy rebuild kits from any pwc or motorcycle shop for around $50 and it's not a difficult job.

In addition to the other fine suggestions, if your unit is equipped with a flame arrester muffler, it would be well to check that.

My '98 Daihatzu Terios had a blocked cathalitic converter whatshelwecallit silencer. It did not effect idling but it was powerless until I made a propper silencer with stainless steel pypes and old fire extingwisher body!

Another source of a vacuum leak can be the intake manifold to engine block interface. Loose bolts or warped manifold. I had this on some 50's era farm tractors. Not too likely on a 5 yr old engine.

Ken

My guess would be a partial fuel blockage, probably need to a) clean the carb completely b) put a fuel filter inline.

I'm with you. 5 years with no fuel filter will surely have a good collection of lint somewhere. Especially if gas cans are used.

I would drain the fuel out and then try to blow backwards from the fuel line on the carb. back into the empty tank. With the cap off, there should not be any restriction. If it has any, find out why.

Thanks for the suggestions. Sorry I haven't answered sooner but my computer has been down. When I get some time I will start trouble-shooting armed with all of your info. Thanks again.

Don

Thanks for follow thru an do report findings....too