VH4D wisconsin engine

Friend is having trouble with this engine. Changed points condensor and distributor cap as it wasn't running very well. Now it won't start but will backfire. I told him to be sure of proper sparkplug wires in proper dist holes - he is sure they are right. I haven't personally seen the engine or its symptoms so am just asking if there is something obvious to check. I know nothing about Wisconsin engines other than apply basic gas engine theory.

I did find a service manual on the internet and printed some pages to give to him.

The engine is in a skid loader and needed for snow work.

1342 firing order, from flywheel to output shaft. Jim

WILL HAVE A STUCK VALVE...PULL PLUG, T.D.C, USE ALLEN WRENCH TO DRIVE VALVE CLOSED, ROTATE MANUALLY, DO IT TILL FREE...BE BLESSED, GRATEFUL, PREPARED..

I agree with Nick, those Wisconsin engines are notorious for stuck valves since the generally run pretty hot. I made a tool, shaped like an allen wrench but a little bigger, worked on valve for a while before I got it to go up and down right, as mentioned patience. beats pulling the head since you will probably break a bolt if you do. On equipment engines guys would put a bunch of engine oil down the exhaust at the end of the season to keep valves from sticking.

how come no-one ever checks compression on an engine when they are having trouble. plus it is unclear if it was running then he changed points and cap now backfiring... means firing order is not correct. as said these engines always have trouble with valves sticking and spark plugs seizing in head and bolts breaking when trying to remove head.

I changed points and condensor on neighbors bobcat with vh4d. Old points were burnt to oblivion. It ran good when I left, but he had nothing but problems soon after. Stalling, spitting, and sputtering.... He said he kept resetting the point and it would work ok for 10 or 15 minutes.

He was ready to order an electronic distributor. I stopped over for another look before he ordered the new one. I pulled everything back apart and the innards of the condensor were rattling around inside it. I put the old condensor back in and its been running like a charm ever since.

Just because the condensor is new doesnt mean its good. I've read quite a few similar storys on here.

I never change the condenser when I change points. if it is not pitting the points why change it.

Since it was running before the new points and condenser, that would be the first place to look.

The new points, and especially condensers are notorious for being bad new out of the box.

Double check the installation on the points, the wire connections, the condenser base must be tight to ground. Assuming this is battery ignition, a test light connected from the point side of the coil to ground should come on when the points are open, off when they close. It should flash as the engine is being cranked. If no light, there is no power to the coil or the points are closed or shorted to ground. If it stays on, the points are not making contact or there is a wire connection problem from the coil to the points.

Also check the firing order of the wires, check the cap and rotor carefully against the original. Another common problem, wrong out of the box.

Were the plugs changed? If not, do so just to say you did. They can look good and cause strange problems. BTDT

A compression test would be the next test. Just don't get too many irons in the fire. Do too many things and the problems can be multiplied and the solution may never be known.

I have limited experience with them except on a hand start baler and a skid steer.
With both on those air cooled engines once they got hot . One time. Dang they are hard to start.
change the plugs and Bam, start right up. They get hot almost every time you use a baler and skid steer.
I think they run too hot for plugs. Seams to me this is the only engine I was ever around that liked Champion the best.