I do sime maintenance on a ski trail groomer that has a 1983 om616 as a power plant. it has roughly 3000 hours on it, and ought to last at least 3000 more.

recently it has shown signs of intermittent fuel starvation, it loses power at random after running for 25 minutes or so. sometimes it will stall. in the past a new fuel filter would solve the issue. this time a new fuel filter has not solved the problem.

a bit of history, somewhere in the past the secondary fuel filter was removed, so now it only has a primary.

exhaust colour seems clean.

any suggestions for troubleshooting?

thanks,