18HP Twin Vanguard, Horizontal shaft motor. Uneven surging issue

[XTwarrior1985]

Found the rest of the field mouse while I was pressure washing and using the compressor. Also got better shots of some of the chewed wires. Going out to look at the solenoid now, and then it is pretty much waiting until the parts get in.

 

[XTwarrior1985]

Solenoid was snipped off. Pulled it out and there was just a nub, so no need to worry about that anymore

 

[bertsmobile1]

Does the surface on the flywheel/stator contacts need to be rust free? All the plates that look like they are for the stator/generator on this thing have surface rust. Wasn't sure if that mattered.

EDIT - Might be the spots for the ignition coils actually; they line up with the body of the coils as it rotates.

No
Magnets are not affected by rust coating them
If it was a problem they would have some sort of surface protection applied at the factory
Same story for coils. I have seen laminations fanned out from severs rust & the coils work fine
As for your mower, change your winter lay up routine
At the last mow for the season change the oil then wash the mower, remove the blower housing and leave it that way all winter
Firstly mice will not find the open engine an attractive winter address and if they can not afford to move into a better neighbourhood then you will see them so can evict them easily .
Finally fins should be cleaned annually and wires check for fraying & chaffing so you kill 2 birds with the one stone

 

[XTwarrior1985]

No
Magnets are not affected by rust coating them
If it was a problem they would have some sort of surface protection applied at the factory
Same story for coils. I have seen laminations fanned out from severs rust & the coils work fine
As for your mower, change your winter lay up routine
At the last mow for the season change the oil then wash the mower, remove the blower housing and leave it that way all winter
Firstly mice will not find the open engine an attractive winter address and if they can not afford to move into a better neighbourhood then you will see them so can evict them easily .
Finally fins should be cleaned annually and wires check for fraying & chaffing so you kill 2 birds with the one stone

Thanks for the info and advice. In this case, I bought the mower at an auction 2 weeks ago, so I am just getting around to checking this stuff now. Though, to be honest, if the coils hadn't been damaged I would have never pulled the shrouds.

As for removing the housing, it would require me removing the engine from the frame as the housing is one piece that wraps around the drive shaft. I could open it up and remove the other shrouds, that may help, but even then the carbs and the intake manifold setup allows for some coverage. I will think of a way to mouse proof it over the winter.

 

[bertsmobile1]

I get quite a dew mowers with horizontal engines & shaft dives offered to me for parts because they have a magneto / wiring problem & the owners could not face the hassel of removing the engine to get the cover off.
A lot of them end up having cooked heads because they were never cleaned and the fins were chockers with dry grass &/or mouse nests .
Because of the difficulty most work shops want 3 hours of labour just to diagnose the problem so most people buy a substantially inferriour mower with a cheap & nasty vertical shaft engine .

 

[XTwarrior1985]

Good news everybody! She runs! She's a little cranky when cold, have to run half choke for 4 minutes or so, but once she is warmed up, she runs solid now, no misses or surging. And magically, I was able to finish without any extra bolts lying around making me nervous

One thing I found out, is that this engine gets HOT fairly quickly. After about 6 minutes, I could no longer touch the valve cover. It should not be an airflow issue, as all the fins are pressure washed and blown out with an air compressor. Now I just need to wait for the valve cover gaskets to come in to stop those from seeping all over the heads when I mow.

Thanks for all the advice!

 

[Rivets]

Glad to hear the good news. Most guys never let us know the results.

 

[slomo]

Finally fins should be cleaned annually

Amen to that.....

 

[XTwarrior1985]

Got the gaskets in and mowed the yard. Motor was solid, and the power was up. Before, I'd engage the PTO and the motor would almost stall. Now it is nice and strong, did not sound like it would get near stalling.

I will say, I parked it and shut it off mid Mow to move some stuff. About ten minutes. When I came back and started it, it surged a little bit for 30 seconds. Similar but not nearly as bad as before, and it cleared up quickly. I'm hoping that is more coincidence than an ongoing issue. We will see I suppose.

 

[slomo]

have to run half choke for 4 minutes or so, but once she is warmed up, she runs solid now,

4 minutes sounds a little lengthy. Especially in our 95 degree weather we are having. Sounds like a partial pilot jet clog. I would boil clean the carb.