'82 ATC 200 Engine gets stuck while turning over??

[kormos_93]

I just picked up an '82 ATC 200 (not running, was sitting outside for abut 8 years). Anyway, the engine is not seized, I can turn on the flywheel by hand (I originally thought the recoil might not be releasing so I took it off) (seems to have normal compression), but after spinning it over a few times it gets stuck & I have to spin it backwards hard (makes a snap sound), then it will spin forward again a few turns. Any ideas of what it could be????

[coolpool]

Might be a valve sticking open and hitting the piston? Not sure if that's even possible but....?

[kb0nly]

I'm thinking along the same lines, check the valves and timing chain.

[kormos_93]

O.K, thanks. I'll check it out.

[dougspcs]

I bought a 200M last year that was sitting 19 years and when I got it running it had a sticking valve that caused it to have no compression about every 4 strokes..anyway I found no interference in that engine so you should be ok there.

I used a spray bottle of transmission fluid in the intake with the carb out to lube the valve guides..smoked a bunch when it was done but smoothed the miss out.

Anyway, are you perhaps hand spinning in the reverse direction causing the timing chain to bind against the guide and stop things?

[C.J]

I am gunna put my money on sticky valves as well. I've got a BUNCH of my flat heads that do that same thing if they sit for a while. Just need to give them a good lubin' so they slip an slide real nice like

[El Camexican]

If you heard a metalic "snap" sound from within the engine at the same time that it firmed up I'd recommend removing the head for a look see. Valves don't run straight up and down, so any contact at all with the piston means damage has been done.

[kormos_93]

Well, never figured out what the problem was, but I checked the valves & they are working fine. Even runs & drives fine, but still gets stuck when trying to start it occasionally & I have to spin the flywheel backwards by unscrewing the cap by the top of the recoil. Don't know, but it can't be too serious. I have another trike that does the same thing. (engine is quiet when running, no snapping, clicking or pinging)