hard jerky cord pull

To move forward on this we'll need to get a compression reading on it. You can borrow a compression tester at a auto parts store. It just isn't acting normal.

 

Okay I borrowed a compression tester. Reading on first try at pull (until resistance prevented pulling further) varied. Sometimes maybe 50 psi, sometimes 60 or so. Continuing pulling until resistance felt again (second piston stroke or so), reading goes up to between 70 and 95 psi.

 

I don't see anything wrong with that. If the engine turns over effortlessly without the plug, and the engine only has 95 psi compression tops, then with the plug in, you should be pulling against 95 psi compression, which is perfectly acceptable. If resistance prevented you from pulling further than 50-60 psi, then I'd say you aren't pulling it hard/fast enough. 50-60 psi isn't even enough for the engine to run on. Maybe the compression gauge is defective? If you pull an engine slowly, it will stop and prevent you from pulling further, but if you give it a fast sharp pull, it will overcome the compression stroke that it normally wouldn't overcome when pulling slowly. If you're pulling it fast and sharp, then I don't know what to tell you. Your compression readings are normal. Maybe something is binding in the pull start mechanism that only binds when a certain amount of pressure is on it like when it's on the compression stroke?

 

No the compression gauge is a good quality reliable one, not defective. I do think your suggestion that maybe something is binding in the pull start mechanism that only binds when a certain amount of pressure is on it like when it's on the compression stroke could be what's happening. It certainly seems so. I did manage to get it to start today by having someone else give it a try. With us both having holding the machine down firmly, he pulled VERY hard and fast (much harder than I've ever had to before) through this resistance I've been speaking of, and got it to go. I'm no weakling and could probably pull this hard every time if I had to (and had another person holding the machine too), but something is not right if I have to pull this hard, that's for sure.

 

I think I also would look outside the compression/inner engine workings. Pull the engine shroud the pull start mounts to and see if something isn't evident with the flywheel/recoil start that could account for the problem.

 

When you where doing the compression readings, was the engine locking up?? or where you able to pull it thru all the strokes without too much trouble?????.. Roger

 

Same issue on a Tecumseh engine on my lawn mower. Too much compression on compression stroke. I found the mower onthe side of the road free. It looks as though the guy hit something as the flywheel was off 90 degrees or so. I took the whole thing apart and pulled the piston still probablem when it is all back together.

Did you ever get your issue sorted out. I was stoaked to see someone havin the same problem.

 

E5133t, you need to start your own thread.

 

My issue turned out to be a broken compression release mechanism.
When I took the crank cover off, there it was lying there. I installed a new one and it works fine now. Good luck

 

ok so lets think about this. it gets hard when you pull it. if all water is removed from the pump. iam going to say one of you youe push rods are messed up. take valve cover off. take spark plug off. now pull and see if the valves move. iam about 99% sure thats your problem. your exhause valve isnt opening so all your commpression is building up til you cant pull anymore.

 

Thread's almost 2 years old. The problem's been solved.
The other poster has not been back since posting.