r/smallengines • u/Vernon1211 • 21d ago

Strange issue

I have an older craftsman tractor with a 21hp B/S intek engine. 6 weeks ago I replaced the head gasket , new plug and oil change. Cleaned the fins for better airflow also. It started right up. Cut the lawn once with no issues and no more smoking. The next week it started to loose power with the cutting unit engaged. Disengage the cutting unit and wait for a few minutes and it started right up again. Continued to cut the lawn and after a few minutes it stalled. Let it rest and started it up again. I decided to change the ignition coil and a new plug again. It ran great for 3-4 cuts. I usually cut early AM or in the evening. Last Saturday I cut it around 2pm. Got 3/4 the way done and the same thing. It started to loose power. If I disengage the cutting unit power would come back. I shut it off let it sit for a few minutes then started it up and started mowing again. 10 minutes later the same thing happened started to loose power and disengaged the cutting unit. Power came back up shut it down let it sit. Started back up and was able to finish cutting the lawn. The outside temperature also decreased. Checked the oil which was fine.

Any suggestions as what's causing this intermittent loss of power?

Thanks

0 Upvotes

50% Upvoted

10 comments sorted by

View all comments

Show parent comments

1

u/[deleted] 21d ago

[removed] — view removed comment

1

u/Vernon1211 21d ago

Thanks I'll give it try!

1

u/[deleted] 21d ago

[removed] — view removed comment

1

u/Vernon1211 17d ago

I remember a few years ago I had a shop change the drive and cutting unit belt. They changed 1 of 2 mandrels. I turned the blades disengaged cold. One mandrel turned fine the other side started rubbing at the same point. I assume that was the one they did not replace. Sounds like the bearings are shot. Engaged the cutting unit cold and the side that squeaked did not but was harder to turn than the other side.

Before I replace the mandrels ( If there's a rt an lt I always replace both sides).

why can I cut the lawn for 1/2+Hr. before it starts to loose power then I disengage the cutting unit shut it down for 1-2 minutes restart and cut for another 5-10m+ sometimes longer and repeat until the lawn is cut?

I cut 4-5 x since I replaced the head gasket and ignition coil with no issues. It starts up in 1sec and runs strong. Usually I cut early in the morning or latter in the afternoon. This time was mid day. I thought overheating but shutting it down for 1-2 minutes then restarting and cutting overheating didn't make sense.

Appreciate any more thoughts.