Rebuilt engine hard to turn over, but then loosens up?

unioncreek said:
I have a JD D140 lawn tractor with a B&S 22 hp V Twin engine. I just over hauled then engine and replace the rings because of oil loss. I reinstalled the engine and cranked it over a number of time trying to start it. Wouldn't start got that figured out and started it and ran for a while at varying speeds to break it in. I tried to start it yesterday and it wouldn't turn over. Thought the battery was low on charge. Put a booster battery on and it would crank over. To the top off so I could get to the flywheel. I put a socket on it and it was hard to turn over for a couple of revolutions then got easy. Cranked it over and it started right up. Today it did the same thing. Runs good once I get it started. Any suggestions on what I should do? The first thing I thought was I got the wrong rings, but the end gap was within specs and it cranks over easy after a couple of revolutions. Is it just that tight and will loosen up over time?

Bob
Click to expand...
Stop! Don’t reopen the engine. Reset the valve lash. The clearance has widen and the compression release is not opening up enough to bleed some out. Common Briggs issue. Easy fix. When running new and rebuilt engines valve lash should always be checked and adjusted after initial run in.
 
unioncreek said:
I have a JD D140 lawn tractor with a B&S 22 hp V Twin engine. I just over hauled then engine and replace the rings because of oil loss. I reinstalled the engine and cranked it over a number of time trying to start it. Wouldn't start got that figured out and started it and ran for a while at varying speeds to break it in. I tried to start it yesterday and it wouldn't turn over. Thought the battery was low on charge. Put a booster battery on and it would crank over. To the top off so I could get to the flywheel. I put a socket on it and it was hard to turn over for a couple of revolutions then got easy. Cranked it over and it started right up. Today it did the same thing. Runs good once I get it started. Any suggestions on what I should do? The first thing I thought was I got the wrong rings, but the end gap was within specs and it cranks over easy after a couple of revolutions. Is it just that tight and will loosen up over time?

Bob
Click to expand...
 
unioncreek said:
I have a JD D140 lawn tractor with a B&S 22 hp V Twin engine. I just over hauled then engine and replace the rings because of oil loss. I reinstalled the engine and cranked it over a number of time trying to start it. Wouldn't start got that figured out and started it and ran for a while at varying speeds to break it in. I tried to start it yesterday and it wouldn't turn over. Thought the battery was low on charge. Put a booster battery on and it would crank over. To the top off so I could get to the flywheel. I put a socket on it and it was hard to turn over for a couple of revolutions then got easy. Cranked it over and it started right up. Today it did the same thing. Runs good once I get it started. Any suggestions on what I should do? The first thing I thought was I got the wrong rings, but the end gap was within specs and it cranks over easy after a couple of revolutions. Is it just that tight and will loosen up over time?

Bob
Click to expand...
the rings have to "seat" with the cylinder walls , completely normal . will free up as rings seat
 
Have a question I didn't see asked, How does the crank turn over with not pistons hooked up? Did you use slandered or over size rings? very intriguing problem. Hope I don't miss the answer
 
Problem is solved. The #1 connecting rod clearance was not enough and it would tighten up enough on the crank journal when torqued to specs that made it very hard to turn. Bought a new rod, installed it and engine is running good. Had nothing to do with valves or piston rings.

Bob
 
I'm guessing a malfunction of the internal decompression lever/spring or improper valve clearances. Improper clearances will give a kickback effect much like hydro lock. Recheck all valve clearances at TDC. Most B&S engines can be set at .005" for intake and exhaust, but check manufacturer specs to be sure.
 
You must log in or register to reply here.
Back
Top