1968 Sears 3.5 Spitting Fire

atucker1

Seaman Apprentice
Joined
Jul 19, 2014
Messages
40
I recently tuned up a 1968 Sears 3.5 (made by Clinton). It usually takes awhile to start, so I decided to Seafoam it (in bucket not muffs). Ran it at high idle, gave it a few sprays and then enough to stall it. Let it sit a while and started up, plenty of carbon coming out. Per the instructions, I ran it hard, full speed for a little bit and then shut off. Looked at the video I had been taking and realized that there were several flashes coming from near the intake manifold when I shut it down (also next to the fuel pump, possible a bad fuel pump connection but I don't think that's it.) Would not start, nothing. Waited 5 minutes and tried again. Sluggish and kept dieing. Finally got it to start, after the little fireballs kept coming I shut it off. I can't say for sure but the pull rope feels different when pulling now; the effort is about the same but it feels like in between the hardest parts of the pull (when piston at TDC) it is looser. Anybody have any insight as to what I might have done?
 

atucker1

Seaman Apprentice
Joined
Jul 19, 2014
Messages
40
I saw no problem in doing that at the time...What could I have damaged by doing this? It looks like the little fireballs were coming from the carb/intake manifold area.
 

brim_buster

Lieutenant Junior Grade
Joined
Jul 9, 2013
Messages
1,203
Your never supposed to run WOT in a barrel or with ear muffs thats a no no...:facepalm:
 

atucker1

Seaman Apprentice
Joined
Jul 19, 2014
Messages
40
I understand that now. My question is what would have been damaged by doing this?
 

atucker1

Seaman Apprentice
Joined
Jul 19, 2014
Messages
40
For anyone with a similar problem, it was just the engine backfiring a bit. I adjusted the idle settings to make it more rich and that fixed the problem. The engine was not damaged from the WOT in bucket test, and now runs great, way better than pre-seafoam.
 
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