Craftsman Yard Vac Ran Great for 10 Minutes then Died

Look at camshaft 46 in IPL. 2 teardrop lobes push rods for valves. The cam gear mates with crank gear. Cam gear could have jumped time. Also, 43 Oil slinger/gov can blow up. Can't tell from IPL but cams can have a boomerang compression release - spring loaded and clears away at run RPMs. It can blow up.
 
I never would have guessed that these engines had PLASTIC camshafts. So it again sounds fairly plausible that I overheated it and I guess just severely deformed the plastic camshaft. I'll have to take everything apart to get a closer look. The movement seems so smooth, that my guess is that the gears didn't skip, just the shaft itself got very deformed. Not sure when I'm going to get to this and it's a bummer this free machine is going to cost me $100 or so but it is a nice machine.
 
Not that I would ever do this for a yard vacuum engine, but does anyone make an aftermarket aluminum camshaft for these engines?

There are many USED plastic camshafts for this engine on ebay for like $10 shipped. Given that you only put like 5 hours per year on these machine, I'm thinking about it. But we'll see once I confirm the problem first. I need to figure out how to even get to the camshaft before i can confirm it and then start buying parts :D
 
If it worked and you did muck the internals, then the valves are opening and closing properly as it worked before.
I doubt you have a compression issue, but if you have or can borrow a compression meter, now is the time to use it.
next. SPARK: Does your spark meter spark or not?
next GAS - is it old or dirty or fouled. drain, clean and try again with fresh clean stuff.
You can leave a spark tester in-line with degraded performance to monitor if you get it started. This may help if this is a electric issue of maybe hot coils. doubt it.
 
jviews12 said:
If it worked and you did muck the internals, then the valves are opening and closing properly as it worked before.
I doubt you have a compression issue, but if you have or can borrow a compression meter, now is the time to use it.
next. SPARK: Does your spark meter spark or not?
next GAS - is it old or dirty or fouled. drain, clean and try again with fresh clean stuff.
You can leave a spark tester in-line with degraded performance to monitor if you get it started. This may help if this is a electric issue of maybe hot coils. doubt it.
Click to expand...
Did you look at the video of the valve movement? That can't possibly be the correct. I don't see how an engine could ever run with the valves opening and closing in that order.
 
l008com said:
Did you look at the video of the valve movement? That can't possibly be the correct. I don't see how an engine could ever run with the valves opening and closing in that order.
Click to expand...

It is highly doubtful that you overheated the engine with 10 minutes of operation. The cooling fins and top of engine need to be really caked up with oil, grass, dirt and debris for an engine to overheat usually.

That is an L-head engine, so it is at least 20 plus years old. Valves do look fine from video I watched. Spray some carburetor cleaner in throat of carb and see if it starts. If it does you know you have spark and compression, and have a fuel delivery issue.
 
Tiger Small Engine said:
Valves do look fine from video I watched.
Click to expand...

Are you sure? Did you look at the timing? I don't see how an engine could possibly run with that valve timing. It's doing an intake stroke then immediately an exhaust stroke, THEN with no possible air and fuel, it's doing a combustion and then a compression stroke. How can that possibly be normal? Or am i totally misunderstanding what I'm seeing?

A melted plastic camshaft is the only way I can imagine the engine went from running well to what's in that valve video in just a few minutes.
 
Ok I'm finally getting back to this. I'm not sure how I found the parts list above because I can't get any results from jacks except parts lists for the body. I can't find a parts list/breakdown for the motor. I'm going to assume the camshaft is melted and needs to be replaced.

I do know my motor is a B&S 675 series, but I assume that's not specific enough to order parts off of?

I'm also watching a camshaft replacement video right now and it looks like a big project. BUT this is a larger motor with a metal shaft so I'm hoping my smaller engine is going to be a little easier to disassemble.
 
You must log in or register to reply here.
Back
Top