14 HP Vanguard Turning Only 60 Degrees

[dieseltech]

Hello All,

I'm helping out a family friend by working on his Cushman Hawk utility vehicle. It has 14 HP Vanguard V-twin OHV. The original issue was the teeth on the starter were ground off to the point of no engagement. Apparently you can remove the starter while in the vehicle, however, I opted to pull the engine since there were other things to be looked at and it wasn't much of a hassle. I eventually found the right starter gear, installed it to the starter and reinstalled the starter. While I had the engine out, I changed the spark plugs and the spark plug boots on the coils. I adjusted both coil air gaps and all 4 valves. I also changed the oil and filter. After having an issue finding the starter pinion gear with the right number of teeth, I tested out the starter while on the engine to make sure the new gear would turn the engine over fine. With no fuel or spark, obviously the engine didn't start but I let it turn over for about 3 seconds. All was well. Starter engaged and disengaged fine. I put everything back together and put the engine back in the vehicle. As I went to install the drive pulley back onto the crankshaft I had to turn the crankshaft a bit to get everything lined up. I notice the crank would only turn about 60 degrees total. When it came to a stop it was quite abrupt, not like the engine was just building compression. After checking all the clearances of moving parts and removing the coils to make sure they weren't contacting the flywheel, I removed the engine once again to see if I could get a better look. This is the point I'm at now. I can't find a thing wrong. It almost sounds internal to the engine when it makes contact with whatever it is. I pulled the valve covers to double check the valves and also removed the spark plugs. It's crazy because just yesterday the engine turned over without issue. The vehicle gets driven mostly on gravel and there was a fair amount of gravels around the engine. I thought maybe one of those got lodged behind the flywheel but I can't see anything or hear it rolling around. I gave the engine a good shake while on the hoist hoping to dislodge something but no dice. The point at which it stops turning is just about where the flywheel magnet passes each coil. It will only move back and forth between those two points. I'm thinking of pulling the flywheel next, but I was hoping someone had another idea. Anyone had this happen?

Thanks,
Seth

 

[bertsmobile1]

If the gravel is magnetic then it can get stuck wquite firmly between the magnets then when it gets to the coils whack, full stop, and an expensive one to boot.
Pull off the fly wheel and have a good look.
Even one of those tiny schroud screws or grill screws will bring it to a dead stop

 

[mechanic mark]

Remove both spark plugs & try rotating engine by hand. When you adjusted valves were you on correct stroke with piston at 1/4" past TDC.

 

[dieseltech]

Thanks for the replies. I think the flywheel is just going to have to come off. I have the spark plugs out and even with either piston at or close to TDC I can still manually push down on the valves and never have contact with the pistons. Like I said the engine turned over fine with the starter the day before and then all of the sudden it wouldn't. Somewhere between testing the starter and putting the engine back in (installing coils, covers, air filter housing, fuel lines) is where the issue arose. I'm hoping it turns out to be something lodged behind the flywheel but we'll see. I'll update as soon as I can.

Thanks again,
Seth

 

[dieseltech]

Also to answer the question, both sets of valves were set on the base circle of their cam lobes so I don't think there should be any issue there.

 

[Grassbandit]

did you get the flywheel off? I was thinking that perhaps the magnets underneath may have come loose....

 

[dieseltech]

Well I finally got around to pulling that flywheel and guess what.......a nut for a quarter inch bolt was the culprit. Stuck right in between the interior magnets. The funny thing is I put it all back together and wasn't missing a nut anywhere, so who knows. Thanks for all the ideas.

 

[Tinkerer200]

Yeah, that is strange. Things, nuts, bolts always seem to evaporate when I take things apart. Actually, I had about the same thing happen yesterday, I laid a flywheel down, after picking it up and installing it, the engine would only turn a short ways and intermittently. When I removed the flywheel it had picked up a small stray nut off the floor. Had me worried for a while.

Walt Conner