Craftsman Lawn Vacuum

[bgsengine]

3250 should be fine as long as it runs smooth, although I would bet if we could find exact specs for it somewhere it'd be rated to run at 3600-3750 RPM since it is a lawn vacuum, I would think they'd want them at maximum power output for the torque curve.. so I'd be thinking 3250 is a little slow, but if everything is working just right, then I don't see any problem there..

[lefty]

If I 1/4 choke it, it does rev a bit higher. But it sounds awfully high to me when I do that. But my ear is not as seasoned as a professional. So I may be off.

But the fact that it revs higher when I choke it a tiny bit seems to me like there's still a problem, assuming the governor is properly set. I didn't screw with it so I'm assuming it's ok. And the amount of time it takes to warm up concerns me as well. I'm going to do another leak down when it cools and see if the head gasket wasn't my only problem. Maybe some compression is getting by the rings or valves. Everything looked ok when I had it apart but who knows. Thinking that once it heats up, things expand and it smoothes out. There's no smoke in the exhaust.

[KE4AVB]

You really should get yourself an inductive tach such as a Tiny Tach TTA2. Going by ear really don't cut it. I work on 2 cycles that can easily exceed the OEM max specs if tune to best air fuel ratio. Stihl is one of them in particular that are tune richer to slow them down to max specs. I even had a Craftsman hedger that was shaking itself in destruction due to over revving.

IPL indicates a non-adjustable carburetor. If speeding up when partially choked when up to operating temperature, this is indication that carburetor is set too lean. Either you have a restriction in the Idle restrictor screw (btw is screwed in all the way as it is non adjustable), the main fuel fuel bowl nut, or possible an intake air leak.

[lefty]

I was thinking of the same possibilities. The 3200ish rpm I was reporting was from an inductive tach. I wouldn't be able to tell that by ear but I could tell it rose a couple hundred when I choked it. Just a bit though. 1/2 to full choke bogs it down, which is what I would expect during normal operation. (I really should be saying partial and full choke because a 1/4 movement of the lever doesn't necessarily translate into a 1/4 choke on the carb)

I was thinking air leak as well because that bowl nut and the idle screw are clean. I cleaned them out good. Those tiny little holes. I have one of those watch maker's headgear with the coke bottle lenses. I cleaned them with a tiny wire and then shine light through to make sure I can see through them. Including that tiny little hole on the bowl nut and the tiny one at the end of the idle screw. I also cleaned out the orface for the idle screw.

I'm thinking maybe I need to replace that oring between the air housing and carb. The only other places I can think of that would be sucking area are the two gaskets at either end of the intake pipe.

Do you think the long warm-up time is related?

[lefty]

I did another leak down and I have air escaping at the exhaust valve. There is also air escaping into the crankcase. I know that some air into the case is normal. Between both air leaks, I was losing 34% at 60 pounds. I had trouble holding the flywheel so I was afraid to go much higher.

When the valve spring cover was on, and I blocked the breather, the oil rose up through the fill pipe and overflowed. When I removed the valve spring cover, the exhaust valve leak was able to relieve itself some through there as well so there was less pressure in the crankcase and no overflow.

So I'm guessing I have two leak points, the exhaust valve, and the rings maybe? I may have said this prior but when this came in, the oil was black and below the min line on the stick.

Could these problems get a little better with heat as things expanded? Maybe this is why it takes so long to warm up and even out?

[bgsengine]

exhaust valve leak can cause a lean misfire or bit of surge, lack of power, I wouldnt worry too much about the rings for now, what you describe is pretty normal during leakdown test, rings are not a perfect seal as you know there *are* end gaps to the rings, so there'll always be a bit of air out the crankcase. just make sure your exhaust valve is actually closed (and not on the start of exhaust stroke, or in some cases on compression release) before condemning it.

[lefty]

Thank you. I checked at the top of the compression stroke and a tiny bit past. I verified the location visually through the spark plug hole and was able to confirm by observing the valve spring / stem movement. Going to give the valves a closer inspection in the morning.

[lefty]

So I was checking valve clearances on this and I have about .007 on the intake and .006 on the exhaust. Now if my model crosses to an LEV100, I believe it's within spec. The docs I have show .004-.008 for both intake and exhaust.

The doc I have does not have a cross-reference for my exact model. I have a craftsman 143.994510 and the closest I can find is a 143.994500 which crosses to an LEV100-345013C. I would think that would be me but I also see a 143.994502 and 143.994506 in the chart, making me wonder why mine isn't there.

The 502 is also an LEV100 but the 506 is a TVS115. I can't find this exact one but there are several TVS and 115's. They are all showing .004-.008 for both valves so I'm going to guess this is where it should be and I'm ok on clearance. If that's the case, I'm going to assume a good lapping may solve my exhaust leak problem. Am I on the right track?

Sorry for the confusing wordiness of this one.

[lefty]

I know I should have done these valves when I replaced the head gasket but I didn't. So I'm wondering if this means I need another head gasket if I remove the head again. It was the one that's part metal.

[KE4AVB]

143-994510 crosses to LEV 120-361053B