Another bout with the 1641
 

Alright folks,

I plowed all winter with the 1641, and for the most part she ran pretty well. Wanted to hunt up and down a little while at lower power. I stripped most of the deck and prepped and painted it. New deck belt. Removed, and cleaned that pesky solenoid in the carburetor. Took the steering apart, tightened it all up(got it a little too tight, may need to readjust). I put her all back together tonight, and take a few laps. Runs ok. Fire the PTO, and she smokes. I let it run for a while, to see if it's just burning stuff off. I mowed for a little while, but kept losing power, and getting smoke. Engine would hunt up and down while PTO engaged, also. I did spot some fresh oil under the air filter housing, right near the hose that goes into air filter area.

Last year, she ran well with PTO engaged, and would hunt more without a load. I'll check around tomorrow, but thought I'd check back here also. Ideas?

Sooo...... what's your question?

You want to know where the smoke is coming from? Or the oil... or why the engine "hunts"? Your post reads more like a story than a question. :Unknown:

Sorry about that. I can't seem to figure out why it's losing power. I'm not sure if the smoke is related at all. When running the PTO, sometimes it will sound as if the motor is about to shut off.

I'd do a compression test on it. Just went through the same issue on a Vanguard that had a blown head gasket. Here is the thread.
http://www.onlycubcadets.net/forum/s...ad.php?t=37590

Ditto to the head gasket.

Well, I was attempting to get down to the head, and it took me a little while to get all the metal free, after finding all the bolts. I opened up the carb again, and there was some more crud in it, so I cleaned it back up. It was pretty filthy under that metal, I've never had it all the way off, so I know I've never cleaned under there. I suspect that as oil has spewed all over, it really caused it to gunk up, and trap all that crap.

A few things I found... Some oil under the air filter (pic. attached). It also appeared that the choke had been bent down, and I don't think it could actually open up all the way. It would hit the metal bracket where the air filter mounts. I also picked up a fuel filter today, because mine didn't look too great.

I've put in a few pics just so you can see where I'm at.

I did find a crack in this tube attached to the air filter housing also...

Pull the engine out of the tractor. It's much easier to work on it on the bench. I'd be willing to bet that the cooling fins are packed full of crud and that it got hot from what I see in the pics. The black oily residue under the exhaust port is pretty good evidence that you have a blown head gasket.

Got the valve covers off. I'm away from computer with only my phone. Not entirely sure what to do next...

Well. I took the top part of that out, but haven't gotten the head free yet. I'm sure I'm missing a bolt or something. To be honest, im nervous as a cat, afraid I might be in over my head... I'll be consulting the manual this evening.

Looks like one head bolt, still in it.

Are you trying to do this in the tractor with the tin work still in place? Why do you have the top of the carb removed? Did you do a compression test? If so what were the results?

I had cleaned the carb. First and hadn't put it back together yet. And, yes. I don't have a garage, and don't want to take too much space up in this one, as it's not mine. I may have to just pull it out. I can't get the rear shield/tin? Off. On compression, I didn't have the tools, but when I started to examine head there was visible seepage.

I found a vanguard manual, looks like it only has the 4 head bolts. I'm pretty green, on anything after the basics. Im moving slow, just trying to learn and not screw it all up.

Well you need to remove the blower housing in order to get at the intake manifold bolts. That has to come off because it's bolted to the heads. That's probably why you can't get the head off.

Thanks, Sam. I'm beginning to think I'm one of those folks who shouldn't own tools. Got the heads off. Anything look strange to anyone, or do I just clean and start replacing gaskets/reassembling.

Case dealer has head gaskets for $15 each. Is that good?

Sorry. It only posted the one picture. I'll get more up soon

Exactly what I expected. It has been over heated because of the buildup on the cooling fins. Get us the numbers off the tag on the engine and I'll look up the parts for you. They have a couple different head gaskets all depend on the engine numbers. Last set I bought were about $6.00 each but they do run upwards of $16.00.

Edit: Hope you pulled the engine because if one head looks like that the other one is probably just as nasty.

Yeah, it's filthy! I believe the number on the engine is K-517004. Mower- model # 142-653-100. Serial # 823808. Thanks! You guys have no idea how much you have been helping me.

Engine will have a tag on it and it should have a number something like this.

351447-1180-A1 this is just an example of a Vanguard number.

Is this the tag (attached picture)? If so, 303447 - 0447-01 -

Yep that's what you need in order to get the correct parts.

Maybe, this is a dumb question... Do you guys use any type of gasket sealer, when installing head gaskets, or just make sure everything is nice, and clean, and flat?

Hoping to get back to the Cub soon, but Momma's Minivan needs some suspension work this week...

No sealer. This is a good how to get your heads nice and flat.
http://www.onlycubcadets.net/forum/s...ead.php?t=5656

Well, it's been a couple weeks, but I've been slowly but surely making progress on the 1641. I got the heads, and rest of the engine pretty well cleaned up. changed the head gaskets, and Valve cover gaskets. Three of the push rods had quite a bit of play, so I adjusted them. The choke was bent down, and not opening back up all the way, and I got that straightened back out.

I put it all back together, and then changed the oil. Started up great, but then started trying to backfire. I checked the PTO, and it seemed to run fine.

So, before it was bogging down, to the point of shutting off, under PTO load. Now, it seems to run great under load, and it will full on backfire with the PTO off. Could this be a carb adjustment, that I somehow messed up, when putting everything back in place? Could it be the push rod adjustment?:bigthink:

Check the push rods again and the carb.

I haven't had a chance to get back to the cub yet, but was reading some old posts around here that got me thinking. I'll readjust the valves, but could this be a timing issue? I did turn the motor with the heads off while cleaning up all the carbon...

And how would that have knocked a magneto ignition out of time? :Unknown:

I have no idea. That's why I was asking. I don't completely understand how these engines work... Yet.

It's not out of time. Ignition, or valve. It's fixed, non adjustable.

Worked at the cub some more today. Whether the valves were an issue, or not, they weren't close to where I should have had them, so I adjusted those.

I ran it for a while with the PTO on, and sure enough, when I shut the PTO off, it was trying to backfire. It didn't shoot any visible fire out the exhaust, and was happening at a slower rate. I went about trying to trouble shoot. Mind you, as this thread already shows, I don't know much about these machines. When I pull either spark plug wire, the backfire seems to go away, I don't think that tells me anything. So, I go to take air filter back off to look at carb, while running. With the air filter off, it seems to run fine. I just purchased this one around January, If I recall correctly. I cleaned it up as best I could, and put it back on. It still backfires some.

I guess my question is do I need to still adjust the carb, to let more air, or less fuel through? If so, do I just start at standard settings, and tweak from there?

Got the carb. Adjusted again this weekend. The 1641 is mowing great! Whenever I shut PTO off it still wants to miss, or fire a little bit, but only at open throttle. I adjusted it just barely over idle. It will run there, or about halfway up perfect. Was looking at a manual, and I might be missing a spring. Perhaps I dropped it when pulling everything apart.

It's #4 in this pic.

http://www.partstree.com/parts/cub-c...gine-assembly/

Not sure if you need #47 or #48

It's been a couple of busy weeks, and I haven't had a ton of time to fool with the Cub. I rechecked the carb to be sure there was no junk in it. Readjusted it as well. Still idles well, and runs under load well. I'll keep searching to see what I can come up with.

Will it hurt the tractor to continue using it in this shape? As I've mentioned it only seems to fire through the exhaust at wide open throttle with no PTO load.

My next stop will be to check the intake gaskets again, maybe I got one backwards, or something. Scratching my head over here, but where there's a will there's a way...

I keep tinkering, but I still have to use this tractor too. It's been mowing well, as I said last time. Was mowing today, and the blades just cut off... Stopped... I drove it to the house, and shit it down. I'm thinking it might be the PTO switch. When I tried to restart it, the fuel shut down solenoid doesn't click back, again.

I'm the shut down solenoid were the issue, the tractor wouldn't run. Maybe, if it thinks the PTO is on it just won't try to start. I'm not "allowed" to work on it today. Promised my wife I'd be around for dinner...:biggrin2:

I'll check the wiring diagram, and be back at it soon! I'll give update when I can.

Old tractors, and old cars. Fixed the power steering on the van yesterday... I'd rather work on the cub.

I'm an idiot. Dead battery.:bash2:

Thats ok,
sometimes we all overlook the simple things or we "assume"