Fs90r wont take throttle

[slomo]

Actually no its a 4 stroke took balve cover off to inspect rockers/clearances

I stand corrected. Model number sounded like a 2 stroke.

 

[Hammermechanicman]

It is not exactly a conventional 4 stroke engine. It is a hybrid 4 mix engine. It uses primary compression of the crankcase like a 2 stroke. That is why it needs mixed fuel to lubricate the crank, cylinder and piston. You troubleshoot these a little different than conventional 2 or 4 stroke engines. The first thing you always need to do is check the spark arrestor and the valve clearances and that the rocker cover is sealed tight. If the rocker cover is not sealed it loses primary crankcase compression.

 

[slomo]

It is not exactly a conventional 4 stroke engine. It is a hybrid 4 mix engine. It uses primary compression of the crankcase like a 2 stroke. That is why it needs mixed fuel to lubricate the crank, cylinder and piston. You troubleshoot these a little different than conventional 2 or 4 stroke engines. The first thing you always need to do is check the spark arrestor and the valve clearances and that the rocker cover is sealed tight. If the rocker cover is not sealed it loses primary crankcase compression.

Wow, I had no clue. Thanks for the engine info.

 

[Gramp75]

In that case i suppose valves could get carboned up?

 

[Fish]

Here is a tech bulletin on carbon.

 

[slomo]

Probably Techron in a bottle.