I have a masport Tecumseh mower model number TVS90 43754P.It starts but revs up and down then conks out I've changed the paper filter and empted the fuel tank and put clean unleaded fuel back in any information on what would make it to do this would be great :confused:

I'd give it a carb overhaul, gaskets/needle and seat and a good carb cleaner soak taken apart.

Hi,
Did you check the spark plug? It could be a little "rusty", might need cleaning or replaced, and the gap checked.

Hi,
Did you check the spark plug? It could be a little "rusty", might need cleaning or replaced, and the gap checked.
Usually surging doesn't happen with the plug (not saying it can't help it surge) but its usually the main jets clogged if its surging when at full throttle.