MTD runs then quits going forward/backward while the engine is still running

[codan]

18 Yard-Man/MTD
42"
16 hp, original engine
About 500 hours on it
NOT hydrostatic drive, it is a belt drive

Yesterday finished mowing about 2/3 of an acre, during the mowing the following happened a couple of times.
1) mowing along in 4th gear
2) forward motion slows from normal to 50% over the space of about 3 seconds but ENGINE IS RUNNING *AT THE SAME SPEED*
3) this last for 2 or 3 seconds, short enough that I'm not certain it is happening
4) then forward motion resumes at normal speed

I finish mowing then park it, then do a little testing and the following happens.
1) moves forward just fine for about 5 seconds after starting, then slows, then stops but ENGINE IS STILL RUNNING AT THE SAME SPEED
2) does *exactly* the same thing in reverse
3) when I switch from forward to reverse (after it has stopped moving), or reverse to forward (after it has stopped moving), it runs in the appropriate direction for maybe 3-5 seconds, then slows down but the engine is still running at the same speed

My guess is belt related but I don't smell any burning or heat, no smoke from burning grass underneath. Note belt is only 1 season old, maybe 25 hours.

Mower is pretty worn out so I'm trying to make the decision to kill it or not.

Suggestions?

Many thanks,
Dan

 

[SeniorCitizen]

Keep your fingers on the key switch and quickly kill the engine as soon as the motion begins to slow. Do not touch the clutch pedal. Step off and check the two motion belts for tension. They should be approximately the same.

 

[codan]

FIXED - well, I applied my massive brain power and decided to give it the best cleaning I could. Cleaned a lot of gunk out.

And it works!

Odd that there was no smell or smoke from burning grass, dirt and belt, but can't argue with success.

Thanks

 

[SeniorCitizen]

Thanks for letting me know I won't ever need to tax my brain again.