Here's one to diagnose.

Hi sgkent,

I am only making a guess like others have, we have not heard the actual cause from Star Tach yet. He likes to give mysteries and brain teasers.

Yes, those pumps can be a little tricky because they are often mounted backwards on a bracket. I always remember that the atmospheric vent is in the middle top and the vacuum pulse line is the closest one to that, so it connects first.
 
Intake could have a crack on it. The intake seal at cyl head hard and not sealing, intake gaskets are wrong or installed incorrectly, carb is not clean enough the jets are still dirty, clean the top plastic jet and port in carb and mixture screw making sure small black o rings on plastic jet are still on and not damaged, check for worn out carb at throttle linkage.
 
And think the DIYer has been using this mower for nearly a year before he decided to bring it to my shop.

When it did come in it had multiple problems. Five listed below. Three of which he induced.
  1. Carburetor was dirty.
  2. Both intake manifold o-rings were damaged.
  3. Fuel pump impulse hose was the wrong one, installed incorrectly, and had develop holes.
  4. Rocker cover was leaking due incorrectly applied RTV sealant and looked like the wrong type.
  5. LF tire going flat.
Fix all these to just get to the root cause of the surging and it is one not normally seen. I had one similar to this a couple years ago so it was still fresh on the brain cells. It had to be a valve train, spark related, or governor issue.

First I check the exhaust to see if it was a completely dead cylinder and it wasn't. Still surging holding the governor arm steady so that ruled out a governor issue. So I was just going to a try a new set spark plugs when I found the stupid mistake made by the DIYer and its one that can happen to any of us if we just skip a vital step.

What was the problem you ask. It was the spark plug tip air gap. It was only .002" when it was suppose to be .030". This was causing a random miss fire and an ignition timing problem.
Normally you don't see this; unless, there is impact damage which there was no sign. So it had to installed that way.

Isn't experience a great teacher? Have a problem that gives you heck to fix once and it will stick with you.

Now it is time to move on the X360 here with a FH661V that been sitting a couple years in a storage building. First I got pass all the rat dropping and I do mean a very large amount of rat droppings and not mice. It even has some cow pies on the tires. Time for the mask and rubber gloves.
 
While you are at it pull the flywheel and fix the the leaking breather cover. Seems like every Kaw engine i have got in lately has either a leaking breather cover or govenor seal.
 
StarTech said:
First I got pass all the rat dropping and I do mean a very large amount of rat droppings and not mice. It even has some cow pies on the tires. Time for the mask and rubber gloves.
Click to expand...
Forget the mask. This is a job for a respirator. I finally bought one a couple of years ago, mostly for mowing in dusty conditions. After using it, I wondered why I hadn't bought one years ago.
 
StarTech said:
And think the DIYer has been using this mower for nearly a year before he decided to bring it to my shop.

When it did come in it had multiple problems. Five listed below. Three of which he induced.
  1. Carburetor was dirty.
  2. Both intake manifold o-rings were damaged.
  3. Fuel pump impulse hose was the wrong one, installed incorrectly, and had develop holes.
  4. Rocker cover was leaking due incorrectly applied RTV sealant and looked like the wrong type.
  5. LF tire going flat.
Fix all these to just get to the root cause of the surging and it is one not normally seen. I had one similar to this a couple years ago so it was still fresh on the brain cells. It had to be a valve train, spark related, or governor issue.

First I check the exhaust to see if it was a completely dead cylinder and it wasn't. Still surging holding the governor arm steady so that ruled out a governor issue. So I was just going to a try a new set spark plugs when I found the stupid mistake made by the DIYer and its one that can happen to any of us if we just skip a vital step.

What was the problem you ask. It was the spark plug tip air gap. It was only .002" when it was suppose to be .030". This was causing a random miss fire and an ignition timing problem.
Normally you don't see this; unless, there is impact damage which there was no sign. So it had to installed that way.

Isn't experience a great teacher? Have a problem that gives you heck to fix once and it will stick with you.

Now it is time to move on the X360 here with a FH661V that been sitting a couple years in a storage building. First I got pass all the rat dropping and I do mean a very large amount of rat droppings and not mice. It even has some cow pies on the tires. Time for the mask and rubber gloves.
Click to expand...
Time to break out the pressure washer.
 
You must log in or register to reply here.
Back
Top