I was tooling down the trail on my 2002 375 Automatic when I lost all power. Coasted to a stop and was surprized to hear it was still idling (rough). When I gave it gas it immediately chugged and died. Same thing now a week later. Starts just fine but won't tolerate any throttle. I've replaced the plug, removed the air filter, and thoroughly cleaned the carb including removing all jets and blasting with cleaner and air. I've also check the gas tank vent and sacraficed a small goat but still no luck.

I asked the dealer about the possibility of the timing chain slipping a tooth but he said he's never seen it and it probably wouldn't run at all. Any ideas?

 

Here is a check list for you, hope something comes close to describing your problem and has the cure for it

Problem: Engine stalls easily
Condition Remedy
1. Spark plug fouled 1. Clean plug
2. Magneto defective 2. Replace magneto
3. CDI unit defective 3. Replace CDI unit
4. Carburetor jets obstructed 4. Clean jets
5. Valve clearance out of adjustment 5. Adjust clearance

Problem: Medium or high speed impaired
Condition Remedy
1. High RPM "cut out" against RPM limiter 1. Shift into higher gear - decrease RPM speed
2. Main jet obstructed 2. Clean main jet
3. Needle jet obstructed 3. Clean needle jet
4. Throttle vacuum piston not operating properly 4. Check piston operation
5. Filter obstructed 5. Clean filter
6. Float height incorrect 6. Adjust float height
7. Starter valve not fully closed 7. Adjust valve

Problem: Engine runs poorly at high speed
Condition Remedy
High RPM "cut out" against RPM limiter 1. Shift into higher gear -
Valve springs weak 2. Replace springs
Valve timing out of adjustment 3. Adjust timing
Cams - rocker arms worn 4. Replace cams - arms
Spark plug gap too narrow 5. Adjust gap
Ignition coil defective 6. Replace ignition oil
Float level too low 7. Adjust float height
Air cleaner element obstructed 8. Clean element
Fuel hose obstructed 9. Clean - prime hose