Hilti DSH700 runs erratic

[plpitts1]

Hello,
I have a Hilti Concrete saw DSH700. Can’t get it to run steady. Will run at high speed, but will not idle unless I turn the low speed needle out about 3 turns. This causes it to eventually race uncontrollably. Has 150 pounds compression. Put new carb and replaced the boot that goes between carb and cylinder, fuel lines and new gasket (runs exactly the same with the old carb and boot). Fresh gas and new spark plug. Seems like its sucking air but I can’t figure out where.
Thanks,
Pat

[HondaG100]

Crank seals. It's about the only thing you haven't changed. I rarely work on 2 cycle stuff but that would be my next move. A little oil on them to help them seal can confirm that is the issue.

[bgsengine]

better yet,do a crankcase pressure/vacuum test and a little soap and water will show you the leak.

[plpitts1]

I will look at the seals. I was thinking that if the seals where going out that it would not run, especially revving. Thanks for the response.
Pat

[plpitts1]

Seals it was, they where actually eat up. Made a pressure/vacuum tester as well along the way. Also when I put the knew seals in on one side the seal just dropped right in, allowing the shaft to have a little wobble. Would have to replace the Motor housing. Don't know if its worth it ($235.00), although I have a new set of seals and bearings already. Thanks for yawls input and making me put together a Pressure/vacuum kit.
Pat

[KE4AVB]

Seals it was, they where actually eat up. Made a pressure/vacuum tester as well along the way. Also when I put the knew seals in on one side the seal just dropped right in, allowing the shaft to have a little wobble. Would have to replace the Motor housing. Don't know if its worth it ($235.00), although I have a new set of seals and bearings already. Thanks for yawls input and making me put together a Pressure/vacuum kit.
Pat

Depends on the condition of the saw and customer. These saws sells for over 1000.00 usd new at Home Depot.

[HondaG100]

Are you sure the housing is worn and the trouble is not just worn out bearings? I don't believe I have ever seen a small engine with spun bearings but others here likely have.

[plpitts1]

Well, the first time I pulled it apart I saw that the seal was at an angle or not sitting flush and was damaged. I ordered new seals, which come with bearings. Installed the new seals and bearings. The unit went out on 1 rental and came back in the same condition, seal damaged. Did not notice the wobble at this point, just assumed I had not put the seal in correctly. Thought maybe I did not push it all the way in since the outer rim was what was eaten up. So I went to install a new seal (the bearings are already new) and that is when it just dropped in, and I noticed the wobble. So that is where I am at. This is a rental unit and I could get the money back on it after 4 or 5 rentals.
Pat

[KE4AVB]

Check that crankshaft while your at it. Sound like there might be a problem with it too that's beating that bearing set up. I have heard of problems with some cranks out there; haven't seen any here in the shop yet.

Would assume that both sides are using the same bearing but I could be wrong (no ipls to look at). If so try measuring both opening and compare that way you know for sure if it is a damaged housing or you just got the wrong bearing sets.