enjoymentboy

I picked up a used chainsaw engine the other day that just refuses to start. It has no labels or casting marks that I can see other than 2.1 stamped on the cylinder but I was told that it "may" be a craftsman. The owner couldn't remember. It has a very nice spark. Fuel is drawn into the carb and I can smell gas in the exhaust port so it is moving through. WHen I spin it it starts to "puff" and then a shot of smoke comes out if the carb. There is a hissing sound coming from the carb as well and I can actually see a fine mist of fuel spray out of the carb when it is spun fast enough.

This engine has the carb mounted to a plastic plate that is bolted to the crankcase rather than the cylinder and I don't think there is anything keeping the crankcase presurized. It seems like any air\fuel charge is just getting blown back out the carb on the down stroke.

I don't see any reed valve or even any indication that one is missing. Does this make any sense? Did any makers even use reed valves in their chainsaws? I am quite sure it's 33cc, hense the 2.1 (cu inch maybe?). The oil and fuel tanks are integral into the crankcase if that helps. No removable tanks on this model.

Any ideas on this? Silly me I spent all my time cleanig it and mounting it and what not before I even tried to see if it ran. I'd hate to find out that I wated all this time.

Thanks.

Enjoymentboy

w8ye

My Feedback: (16)

When a engine has a sprung or broken reed valve it will just pop but never run.

Non reed valve engines if they have a crankcase leak or bad seal will do the same thing.

Several engines have the reed valve on the side of the crankcase. Where the carb mounts expands out somewhat where it bolts to the crankcase. This is where the reed valve is.

If the reeds are just sprung, see if you can turn them over to make them tight. If you see a crack in one, it will have to be replaced. If a chainsaw dealer cannot fix you up, maybe you can make one?

Enjoy,

Jim

enjoymentboy

Thanks Jim,

I don't see any reed or part of one there at all and in fact I can see the crankshaft when I open the carb all the way.

Any idea as to which engine maker may have used reeds on their 33cc engines? Maybe I can find one and "make it fit"?

I'd hate to loose this engine. It looks to be in great shape and is pretty much ready to go.

Thansk.

captinjohn

Post a photo....we can help...Capt,n

enjoymentboy

Unfortunately no pics are possible. Dropped the camera on the garage floor last week and it's slightly dead.

I have done some searching online this morning though and from what I can tell this was a Sears chainsaw from the early '80's and it should have been made by Poulan. I couldn't find any pics of the actual engine but I saw a few cases that looked real close.

I'll see about borrowing a camera to get you all some more details but I'm getting more confident that it is a Poulan so I'm going to look in that area for reed valves and intake parts to see if I can find anything that looks like it'll fit.

Richard

Rupurt

If you can see the cranshaft through the carb, I am pretty sure you are gonna require some kind of valve. If you cant find one, making one shouldn't be to difficult. I am sure you wont loose the engine it just may take a little more than usually to bring back to life.

Good luck!

enjoymentboy

Well..I have a line on a valve, box and carb from a Homelite that "may" be able to be worked to fit. I'll take a look at the intake tonight and see if it looks possible. Failing that, are there any links that anyone knows of that may be able to direct me, as far as how to make my own reed valve?

I may just end up having to go that route.

Richard

Rupurt

Maybe if you are in searching mood you could poke around some of the old ryobi 31 posts, I can remember when it was but I saw guys making reed valves to get the most out of there ryobi engines(it might have been the boat guys).

Flypaper 2

Poulan model 25, 25DA, or 25CVA are 2.1 cu.in. It has a large reed valve screwed with one screw under the piece that the carb bolts to. I would take it apart as the broken reed will still be somewhere inside the engine.

enjoymentboy

I was able to borrow my neighbors camera for 3 minutes just before he left for work. These are not the best shots but I hope they help. You can see the engine from the side, top and then the bottom of the intake where the reed would screw on. Clearly no reed there but it's not in the engine either. I am quite sure I can make one that would work there. Simple enough of a shape. Just don't know what would be the best material to use.

Richard

enjoymentboy

This just isn't my day. Arrggg!

I spent about 1/2 and hour and I have made up something that is at least passable as a reed. I cna blow a good amount of air through the carb and it opens well enough and when I draw air back into the carb it seals right up. I don't know how long it'll last and I'd rather use fiberglass or carbon fiber but this looks like it might work.

Now after all that I find out that the woodruff key is toast. It looked fine but when I took off the flywheel I found part of it on the bench. Now I have to find one of those.

1/16" x 3/8" sound like an accurate size? That's what it looks like to me. It is the same as the one on my 33cc Homelite ZR series chainsaw if that helps.

I AM going to get this thing running if it kills it.

Richard