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compression release on cam

#1

B

bizybily

I have a huskvarna mower with a briggs 22HP intek, (44R677-0004-G1. Very hard to turn over and I expected the problem to be the compression release on the cam. My question is does this engine have the compression release.


#2

StarTech

StarTech

this should answer the question. First before blaming the ACR try adjusting the valves to spec. Intake valve appear the lower valve in the head due to cross flow design. Once adjust to spec rotate engine through at least two complete turn obversing the rockers for a slight bump as the piston reach TDC compression stroke on each cylinder.
1715271686531.png


#3

I

ILENGINE

StarTech said:
this should answer the question. First before blaming the ACR try adjusting the valves to spec. Intake valve appear the lower valve in the head due to cross flow design. Once adjust to spec rotate engine through at least two complete turn obversing the rockers for a slight bump as the piston reach TDC compression stroke on each cylinder.
View attachment 68589
Click to expand...
The Intek V-twin doesn't have the crossflow heads so the intake should be the top valve with the compression release on the #2 exhaust


#4

StarTech

StarTech

Then I stand corrected on the heads but that camshaft looks like it is able to do both exhaust valves then.


#5

Tiger Small Engine

Tiger Small Engine

StarTech said:
Then I stand corrected on the heads but that camshaft looks like it is able to do both exhaust valves then.
Click to expand...
I recently had a customer call and say he thought it was a bad compression release on his mower. Had been reading online. Turns out the engine was completely hydro locked with fuel. Another Nikki carburetor o-ring caused all the problems. He couldn’t be bothered to simply remove the spark plug and crank the engine to see the gas come shooting out. He was glad when I told him because it saved him lots of money. People are funny. It is like having a medical issue and reading about it online and diagnosing yourself sometimes.


#6

StarTech

StarTech

Yes they are. Sometimes they think they know more than the doctors (mechanics) but even we can get suck in at times on misdiagnosing a problem. That is why we got to take our time and do a proper set of given tests. First we need to start with the basic checks and then follow where they lead us. Just be aware some things has multiple problems which each must be resolved. These multiple problems can cause false leads but we resolve then we gradually get the real problem.

An example is the Briggs 31R I am working on. Now I am at least the fourth mechanic to work on the problem. They got no where on it. Even JD tech gave up on it. Initially customer came in with just the starter for a new pinion gear. Then the mower showed. Sever kickback from a bad camshaft. I got that fixed and a new starter Bendix installed. It was running like it should so we loaded it up. Well with a few hours the customer was back with the engine surging like crazy. Now I am think that the crankshaft timing gear wood ruff might be sheared due to the ACR jamming the gear train but I will not know for sure until I pull the engine again. If it is sheared it be the first for me have happen. But had only checked last time by quickly looking at the keyway, I should had done a better check considering the starter pinion failure.


#7

PTmowerMech

PTmowerMech

StarTech said:
Yes they are. Sometimes they think they know more than the doctors (mechanics) but even we can get suck in at times on misdiagnosing a problem. That is why we got to take our time and do a proper set of given tests. First we need to start with the basic checks and then follow where they lead us. Just be aware some things has multiple problems which each must be resolved. These multiple problems can cause false leads but we resolve then we gradually get the real problem.

An example is the Briggs 31R I am working on. Now I am at least the fourth mechanic to work on the problem. They got no where on it. Even JD tech gave up on it. Initially customer came in with just the starter for a new pinion gear. Then the mower showed. Sever kickback from a bad camshaft. I got that fixed and a new starter Bendix installed. It was running like it should so we loaded it up. Well with a few hours the customer was back with the engine surging like crazy. Now I am think that the crankshaft timing gear wood ruff might be sheared due to the ACR jamming the gear train but I will not know for sure until I pull the engine again. If it is sheared it be the first for me have happen. But had only checked last time by quickly looking at the keyway, I should had done a better check considering the starter pinion failure.
Click to expand...

Those multiple problems with one issue can turn into a real headache. Test something fails, fix that and the test still fails because it wasn't just the one thing you fixed.
All that head scratching leads to a bald spot.


#8

I

ILENGINE

PTmowerMech said:
Those multiple problems with one issue can turn into a real headache. Test something fails, fix that and the test still fails because it wasn't just the one thing you fixed.
All that head scratching leads to a bald spot.
Click to expand...
And customers want an estimate prior to doing repairs. And the key switch is damaged and the replacement they supplied when the mower was dropped off doesn't appear to be the correct one and starter solenoid is sticking at times which has damaged the starter, the motor is lose and doing the wobble bang on startup, When cranking it also appears it needs the valve clearances set. but the issue that prompted the customer to bring you the mower was it will not stay running, after starting.


#9

B

bizybily

Tiger Small Engine said:
I recently had a customer call and say he thought it was a bad compression release on his mower. Had been reading online. Turns out the engine was completely hydro locked with fuel. Another Nikki carburetor o-ring caused all the problems. He couldn’t be bothered to simply remove the spark plug and crank the engine to see the gas come shooting out. He was glad when I told him because it saved him lots of money. People are funny. It is like having a medical issue and reading about it online and diagnosing yourself sometimes.
Click to expand...
Thanks for the input. It was the valves. I adjusted them and now it turns over like it should


#10

PTmowerMech

PTmowerMech

bizybily said:
Thanks for the input. It was the valves. I adjusted them and now it turns over like it should
Click to expand...

You're lucky. Because replacing the cam is a major teardown.


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