QuestionB&S 13 HP Diamond I/C engine on Dixon ZRT mower.
Start of 4 cutting season. Engine has been well
maintained and store in carport when not used.
I maintained all types of gold course equipment for 2 yrs including overhual and repair of B&S engines.
Problem #1 (see #2 also)
Engine started overheating. Engine sounded as
if it were running under heavy load. I shut
engine down and allowed to cool off. Engine
turned freely and seemed to run at idle OK.
When engine was reved up to full speed it
resumed overheating and running as if under
stress with mower disengaged or engaged.
Engine turns freely and cranks easily. Local
dealer is stumped also. We've done the following:
Remove cowling and cleaned fins, etc.
Replace key in flywheel (the old one looked OK)
Adjusted idle fuel mixture
Clean, checked and regapped spark plug
Checked crankcase vent valve
#2 I removed engine to take to dealer. Upon
removal I found a small (1/4") crack in bottom
crank case about 2" from crank shaft toward
cam shaft side that was leaking oil. Crack was located in a spot that was covered by steel decking and we don't suspect something could have hit it. Waiting for the dealer to remove crank case bottom. He thinks crack may be at boss of cam shaft or governor shaft and has effected the valve timing. New crank case bottom, seals, etc will be about $100 and new engine about $450. He has no idea what caused
the overheating and running under load problem
so we're not sure replaceing the crank case will
help that or if the crank case crack could have had some effect on the running problem.
AnswerCheck the cam area. If the cooling fins are intact, all sheet metal on the engine, oil viscoity correct, plug, key and mixture are fine then the only other item is mechanical timging, i.e. valve timing.
I haven't ever had a real cam timing issue, but I have had valve clearance problems cause overheating. This is due to a change in valve duration, how long they are opened or closed.
Since the engine has had a lot of use, I would rule out any type of warranty/defective engine manufacturing.
However, I would check with Dixon to see if they have had any other reports of this "crack". Briggs keeps a tally of complaints/problems if enough people have the same problem. We had a log splitter, can't remember the name brand, but the engines were cracking and vibrating parts off themselves right and left. Very unusual since Briggs tests every engine. Come to find out, the manufacture of the log splitter didn't make the engine mounting location strong enough. To the fix the problem, Briggs got with the company and solved the issue by welding extra brases to the engine mounting plate.
Please keep me updated on the issue. I'm very curious as to what caused the crack.
Eric
