Hotwire K series

[guido]

I thought I knew how to hotwire a K engine.

Battery ground to block.
Battery positive to coil.
Battery positive to A terminal of S/G.

Engine fires. Remove positive to A terminal... engine dies.

Am I forgetting something?

[J-Mech]

Your doing something wrong. Block grounded and power to coil is all you need. That DOES NOT include any wiring to use the starter.

Are you trying to use the ignition on the tractor? Or are you trying to start it on a bench?

[guido]

Gotta be missing something Jon.

I am bench testing this K301 engine. When I stated "positive to A terminal" was only for cranking the engine.

After engine started I removed the wire to the A terminal thinking that I don't want to burn the S/G. Engine shut down when doing so. Engine will only remain running with juice to the A terminal.

[J-Mech]

So, no other wires on this engine??

Maybe you just have the idle set too low...

[guido]

No other wiring. Just what was stated above. The engine quits no matter what throttle setting. Idle, off idle, mid throttle, etc...

I'm trying to put some observations about this engine together in my head.
Seller claimed he tried to get it running but couldn't get spark. The oil is clean. I mean like right out of the bottle clean. Was there no oil when he got it? Water in oil?

Filed points. Set timing. We have spark.
Then the once running S/G wouldn't crank the engine. Further investigation found rusty water in the S/G. Disassemble, hose out rust, and reassemble. All is good with the S/G. Will need bearings soon.

No fuel to carburetor. Clean sediment filter. Never in my life have I seen a carb in such condition. Tar, rust, calcium deposits. Clean and reinstalled.

Crank, Crank, Crank, Vrooom. Well would you look at that! The exhaust is spraying rusty water all over the wall of my trailer.

I ask myself, "could the water in the muffler create enough back pressure to keep the engine from running?" I'll have to remove the muffler and try again tomorrow. (and change the oil just for good measure)

[J-Mech]

Well.... whatever the issue is, if you have power going to the positive side of the coil, the points are clean and it has spark, that's all the wiring you need. Outside of a wire to spin the starter. You must have another issue somewhere.

[R Bedell]

Is your engine wired like this....?? Bench Wiring

[stimpy]

yes water in the muffler can cause a back pressure problem and a sticky exhaust valve ( I would check it to see if the stem has any rust ) . smaller single cylinder engines are more sensitive than bigger ones . , I know on Onan twins ( 50 CiD, 886 CC ) they have a back pressure number listed in there service manuals and its like 50" Wp (3"hg) which is like 1.5 psi max .

. if its the stock beer can style , instead of taking it off, drill a 1/16 drain hole in the bottom corner of it this way it will stay drained and also any condensation build up will come out ( with the alky gas we use around here you will see some dripping until the motor and muffler warms up like a car does ) the carbon should protect the steel ( I put a drop of BBq paint over any bare metal with a q-tip but not plug the hole ) , and it will rust just as fast as the rest of the muffler will .

I had a 128 with stock can muffler and a wannabe puller stack ( cobbled on the end of the stock exhaust ) that sat for a long time outside, it turned over by hand , I removed the stack and I suspected water as it would pump some out , so I drilled it and it had about a cup in it , but it still wouldn't start , 24 volted the S/G and sprayed a little ether in it and blew a half decayed mouse carcass and some seeds out of the muffler .. fired right up after that ... ( had to replace the muffler as it stunk real bad when it ran plus blew smoking seeds out of it and was rotted out internally .) and later had to redo the valves as the exhaust would stick open .

[guido]

Originally Posted by R Bedell

Is your engine wired like this....?? Bench Wiring

Thanks for the link Roland. Yes. Except no switches or solenoids. If I would have seen that I wouldn't have had to ask. That will teach me.

[guido]

Thx Stimpy,
With all the corrosion and nastiness I have found a stuck exhaust valve is likely the case. I will drill the drain hole as you suggest. The can is in pretty bad shape anyways.

I got a good laugh picturing that mouse flying across the shop.