That is very odd. I was going to suggest the brake possibility before reading that you had it tied down. Only one idea from experience... I had one that was similar in description but it had actually been straight gassed. Very hard to pull with plug in, seemed to have some compression with plug out, but the tear down revealed almost no bearings on the rod and the rings toast.

these do NOT have a compression reliese device and thats why are so hard to pull. this engine is a pos

Can you do a compression test to determine if the compression is really that high? I suppose it's in the realm of possibility that carbon buildup would increase compression but that's a little extreme.

I had a 'V' on a 10201 for about 12 years, and it had very high compression, but probably not as high as Walt's. I would usually pull the front wheels off the ground when starting it. You don't see many of these around anymore - the mower had lots of issues.

Walt
The 4.5 hp V engines have always had high compression.

They are more related to the Dura Force engine than anything.

I was at my friend's this evening. He has completely disassembled the engine. It did not actually have that much compression. It apparently has/had something binding. Don't know what yet, cylinder and piston are OK, no scoring or metal transfer, bottom ring was stuck half way around, top needle bearing and crank look "odd", no real sign of overheating or leaking seal. Rod throw look good.

I suspected bent crank but he says it definitely is OK. He is a very experienced small engine mechanic just not that much experience with LB and I have not worked with them much for several years.

I think he is going to re-assemble it with new rings and see what happens.

Walt Conner

Walt, I have used pistons, rings and cranks from "V" engines directly into an "F".

The internal dimensions are the same, in fact you can bolt a "V" to the exhaust plate of the "F" leaving that crappy v shaped muffler behind.

So I'd say they are more like an "F" series that anything else.

As for your situation. Is there something with the flywheel? Is the CD pack rubbing it or too close? I know they have high com but that is way out there.
Let us know what you find.

Neal

After asking about the rings fitting, I finally had enough sense to check the part number for the "V" engine and found it said "F rings" then I checked the parts list for one of my "F" engines and found the same number.

Flywheel is not dragging. Now that I think of it, there was a fair amount of carbon in the top of the jug. Am wondering if this raised the compression ratio enough to be noticeable. We are missing something though as it felt as though it had some compression with the spark plug out and I never noticed crankcase compression when turning by hand on the engines I have worked on. (Lots of older ones)

Walt Conner

Walt, I have always felt the crankcase compression when turning the engine over by hand. I also hear a "gulping" at the reed valve followed by hissing as the crankcase compresses and air blows back around the reed (carburetor removed). The main bearings on the "V" I have always seemed way too loose, much more play than the Duraforce, but the seals don't leak so I assume that's normal.

"also hear a "gulping" at the reed valve followed by hissing as the crankcase compresses and air blows back around the reed (carburetor removed)."

Well I remember that OK. I used to work on a lot of LBs but haven't for several years now, just didn't remember feeling crankcase compression.

All needle bearing LBs are loose, I THINK maybe the DuraForce have ball bearings. Haven't had either one of ours apart yet.

Thanks,

Walt Conner

Walt,
Did you find anything amiss? Just wondering.

I haven't talked to my friend for a few days. Last time I did, he had cleaned the carbon out of the jug, cleaned up the piston and put in new rings. He said it felt much better and was going to try to start it the next day. I am curious too.

Walt Conner

Duraforce only has ball bearings on the mains - rod jounal and wristpin are needle bearings. Crank is bigger too - I haven't heard of any bottom end problems with them other than some broken rod caps early.

Well I just talked to my friend. (See thread start) The engine starts and runs great though it does have considerable compression when pulling the rope. I think the "V" does have higher compression ratio than the "F" which is the reason for the square, larger, cooling fins (?)

He did what I said in post above. The fix does not fit the symptoms to me. He says that now it does not seem to have the crankcase compression with the spark plug out. I still feel like this was perhaps the stuck ring binding in the bottom of the bore where there is generally less wear. This plus the carbon build up in the top of the cylinder jug MAY be the answer, I don't know. Anyway, that's it.

Thanks to all for the help,

Walt Conner