I have a 2000 trailbos 325 and i had to take it to the dealer to get it repaird because its been fouling plugs. I told him ive been burning premium fuel in it. He told me that it can cause a loss of compression and cause the jets to clog up. Is this true.
Barry

 

The dealer doesn't know what he is talking about. There is no reason to run premium fuel in any polaris ATV's. But using premium is not going to hurt the engine in any way. Premium is used to keep an engine from detonating either from high compression or from advanced ingition timing. It has its place in high performance engines but a 325 trail boss it is only recomended to use an 89 octane fuel. If the engine is run excessively hot it may help to stop preingition but under normal operating conditions it should not be required. Premium fuel shoud not cause any more carbon build up or plug the carb jets any more than regular fuel. Like I said to began with. Premium is not required but using it will not hurt your engine in any way.

 

I think why you are fouling plugs, is because the motor is running rich, because the Premium fuel tends to be thinner than regular, so it flows easier, resulting in getting more fuel to the engine = Running Rich.

 

Premium fuel is formulated to burn slower,therefore cooler, in high compression engines.Using premium ,or race gas,in any engine that is not set up to burn it will eventually cause problems. The additives in the premium will not burn completely in a stock motor,and leave deposites in the combustion chamber,which is probably causing your fouling problem.Just go back to regular,89 octane max,and you should be fine. Premium fuel thinner than regular,and flows better??!! Good one, mojave300ex.Your main jet is a set orifice,no matter what,only a set amount will flow through it,besides,gas only comes in one viscosity, maybe you were thinking of diesel fuel, they change the formula for winter,thinner than summer blend!!!

Later, guys

 

I learn somthing new everyday, I'm only 13. One of my dads buddys told me that, I believed him!

 

i agree to them all,if the quad is stock,run what the maintenances manual tell wich is 89 regular octane gas probably,your dealer is only
worry about warranty issues,but if you ran that gas for a while with stock head compression maybe some fuel/stabiliser cleaner into the gas tank wil enventually clean up all the possible deposites fuel system and plugs fouling as well.

 

You can also check with a local car club, and find out who sells non-oxygenated regular unleaded in your area. I kinda have to side with Scottaboshia on this one, if you're only stepping up to 92 premium, I don't think you'd hurt anything. I would take a look at the jetting of the machine.

Ken

 

My brother works at a refinery here in Texas and he says to run Premium in high compression motors or when the motor will be stored for a couple of months. He said that Premium fuel doesn't brek down as quick as 89 octane.

Ronnie

 

I am not a chemist, but I cant see where premium fuel (93) is gonna hurt your quad. I ran it for a year and nothing so far has happened.