Now what's wronmg with my Robin engine?

[BobRip]

Here is one. Hard to see, but the cut goes all the way across.

 

[MossRoad]

Looking at my Kohler setup with the variable volume pump ahead of the engine and the PTO pumps behind the engine, I have a stub shaft PTO on the blower cover side of the mower that powers the variable volume pump just like yours. I’d have to pull the gas tank, and move the VVP forward to get enough room to slide the blower housing out over the stub shaft far enough to get to my ignition coils as well. Bummer. If it ever comes to that, I’ll look at cutting the housing as well.

 

[MuncyBob]

Thanks Bob for the pic. Spoke to Terry at PT yesterday and he agrees it's probably a bad coil. Since this engine is to the rear with all pumps in front he advised me to just loosen the pumps(or remove?) the pumps and raise the engine just enough to get at the coils. Seems I'll only need a few inches and have access once the shroud is removed? Going to cut the shroud before reinstalling. I'm hoping this is only a couple of hours work instead of the 6+ that I've read about for others...weather is just too nice out to spend all day in the garage!

 

[cqaigy2]

You might be able to get away with just removing the engine mounts and lifting the whole works up enough to get at the coils. That's what i did to replace the starter motor.

 

[BobRip]

You need to get two sets of feeler gauges to set the coil to rotor gap. I set the first one back several years ago with one and it is way off. I tried to adjust it when I replaced the second coil, but the screws did not want to come out. Since it appeared to be working fine I left it alone.

 

[MuncyBob]

I must admit that I'm a little lost on setting the coil gap. I guess it will make more sense once I get into things.

 

[MossRoad]

I think there's a coil in the flywheel. And then there's your two ignition coils, one for each spark plug. Those two coils have to sit within +/- X distance of the coil on the flywheel. As the flywheel spins, it creates current in the ignition coils. Too big a gap, little-to-no spark. Too small a gap, your coils grind together like a lathe.

 

[cqaigy2]

See if i can get this picture to post here. It shows both coils there at the top, on both sides.

 

[BobRip]

That about where mine are. The gap was 12 to 20 thousands.

 

[MuncyBob]

Since it bugs me that sometimes(too often) the user never posts the results...here's what happened.
FIXED!!!!!!!!!

I've read some posts that seem to indicate that this was a 1 man job...maybe, but not for me! With an extra set of hands both coils are replaced, engine oil/filter, hydraulic filter change and re-route of fuel line to make the shut off valve more accessible, new fuel filter, engine cowl cut for easier access if/when needed took the 2 of us just over 3 hours. This was after I removed everything that needed to be removed and rigged up a block & tackle to pull the engine up. It's been a long time since she ran this good. I suspect I've been running with coil(s) going downhill for too long! I ran it cutting grass for about 1.5 hours and later ran it again with the bucket for about 45 minutes...except for me forgetting to open the fuel shut off at the 2nd start everything went great.

My friend is going to have the old coils checked and maybe one of them will be good enough for a spare in the future. This was an eye opener for me but it all makes sense now....I'm much better at spreadsheets

Thanks to all for the help here....much appreciated!

 

[BobRip]

I noticed a big difference when I changed one coil.

 

[BobRip]

I noticed a big difference when I changed one coil. How old are your old coils? I would not reuse if more than say five years old. It can be hard to tell if a coil is bad in a tester.

 

[cqaigy2]

Wow!
Sounds like you modded and got your tractor all up and running. Gives me encouragement so when i have to dig back into things for repair or modding. I've got to reroute my shut off valve too. Could you post a picture?

 

[MuncyBob]

I'll try to get a pic later today but essentially I used a 3' hose and ran from the tank outlet towards the front of the tractor and looped it around the pump to run to the filter at the back of the tub. The shut off is now in front of the gas tank and easily accessible once the lid is lifted.

 

[cqaigy2]

That description will do just nicely! Thanks. I'll be getting some 3' of fuel line.

 

[MuncyBob]

I took some pics so you may as well see them anyways. The first one is the gas tank connection and the second shows the route I took.

 

[cqaigy2]

Thank you.

 

[MuncyBob]

Yea Bob, I don't think this tractor ever ran this good! I expected easier starting in cold weather with the better coils but it seems to have a bit more power and certainly runs smoother. The coils are 13 yrs old so I'm not expecting much good from the tests.

 

[BobRip]

I would be interested in what test he is doing on them. I tested mine and it tested OK with a spark tester.

 

[MuncyBob]

I don't know what was used to conduct the test but I was told both were bad. Apparently they are rated at 12k volts and they were only doing 2k?

She is running sooooo good right now. This and the side exhaust fan/Robin manifold mod are the best 2 things I've done with my 422.