Intek 40 Series Pushrod Length vs Adjustment Range

[Dave_C]

Before this engine popped out the valve guide, it had plenty of power for mowing.

Should the valves for just this one head be lapped while the head is off, or will this potentially be worse, causing a difference in compression between this cylinder and the other cylinder which won't get the valves lapped?

I realize that best practices would mean lapping valves for both heads, but I'm running out of time, need to get all the work done on the same visit. If all the leaves get too much rain or snow, they're going to mat down and can't be mow-mulched away.

 

[Tiger Small Engine]

Before this engine popped out the valve guide, it had plenty of power for mowing.

Should the valves for just this one head be lapped while the head is off, or will this potentially be worse, causing a difference in compression between this cylinder and the other cylinder which won't get the valves lapped?

I realize that best practices would mean lapping valves for both heads, but I'm running out of time, need to get all the work done on the same visit. If all the leaves get too much rain or snow, they're going to mat down and can't be mow-mulched away.

Always do visual inspection, lap valves, de-carbon valves, cylinder head, and piston head, and check head for level with feeler gauge on glass. Don’t worry about other cylinder unless it is a problem. Perform compression test to compare two cylinders once work is complete.

 

[Dave_C]

How do you do a compression test on these? I was under the impression that they have a compression release mechanism that's active while cranking, till running higher than a certain RPM. That won't impact the reading?

 

[StarTech]

How do you do a compression test on these? I was under the impression that they have a compression release mechanism that's active while cranking, till running higher than a certain RPM. That won't impact the reading?

This why you do leak down tests and better yet the modified leak down test when an OHV engine is involved. With low pressure leak down tester you can test all of cylinder condition from TDC to BDC. The tester I have test at 12-15 psi to get full scale readings; therefore I can hand hold the flywheel and can rotate through the TDC to BDC cycle while watching the leak down percentage needle. Also paying attention the air is leaking out in case of a bad valve seal or a blown head gasket.

While using this modified test I found several engines with lower cylinder damage that would have no shown up on a standard leak down test.

 

[Tiger Small Engine]

How do you do a compression test on these? I was under the impression that they have a compression release mechanism that's active while cranking, till running higher than a certain RPM. That won't impact the reading?

Yes, the compression release will affect a compression test reading. You are looking for at least 60-70 psi on a twin cylinder with compression release. You are also looking for 10% or less differential between the two cylinders. I sometimes do a leak down test also, depending upon the situation.