Hey All,
Kawasaki FR691V 6 years old. Noticed loss of power fairly suddenly. Went through some basic tests (thankful for wealth of information on this site) and narrowed it down to bent push rods on left cylinder. Being a newb when it comes to small engines, I’m now looking for some direction for what to do next.
Here’s what I know so far:
Engine is running great for being on one cylinder. Can cut grass albeit a little slower and only on flat ground.
The bad cylinder has spark.
There was a mouse nest that is the likely culprit leading to overheating.
When I opened the valve covers there was a lot of oil in the valve case (not sure if that is normal – could be for all I know).
Both push rods were bent. No visible damage to rockers or valves.
Both valves push up and down but I’m not sure what “normal” resistance and length is.
Any help with next steps would be appreciated. I know push rods don’t bend on their own so there is root cause. Would it be helpful to get some new push rods and see how the valves are operating before going any further or is it best to remove the head for further investigation?
check the valve guides, see if they have moved up. most likely the exhaust side. guide will move up so high that the valve keeper hits it before valve fully opens bending push rod. all thanks to the mouse nest overheating head. only real fix is a new head and valves if this happen. pushing valve guide back in place doesn't usually last long before it moves again
What would a valve guide out of place look like - are both valve guides suppose to be flush with head surface? Thanks!
#4
cpurvis
No, not flush. You can take the valve cover off the other cylinder and see how much the valve guides protrude from the head and how much clearance is between them and the valve spring retainer when the valve is fully open. Of course, that assumes that the other side has not had any valve guide movement.
There's not really much other reason for the pushrods to get bent.
#5
Scrubcadet10
They generaly sit 1/8 to 3/8" above the head. .. I think some Kawasaki engines use retainer clips to keep them from falling down.
since a mouse nest on one side cause it other side should be ok. need head, valves, 2 valve seals, exhaust intake and head gasket, push rods as needed, will need to exchange exhaust studs or get new ones.34 ft pound head torque. .004-.006 valve clearance on both valves
Help! I have the new head on and now installing pushrods. But I’m confused as to why the pushrods are not fitting in. Figured I wasn’t at TDC so Spun the flywheel but the pushrods are not moving. Could I have bigger issue with camshaft lobes?
#9
Scrubcadet10
loosen the lash adjuster nuts, i cant remember what they look like on your engine, and then fit the rods in and adjust your valve lash.
and be sure the end of the push rod is seating properly in the tappet. if you can look down the push rod bore with a flash light and see.
Ok. Just had to give them a tap with a mallet. Must have been stuck. Everything back together and running! Exhaust coming from muffler so I’ll to check on that. Thanks!
