motor problem

[Mark K]

I have a woodmizer lt 40 mill. Owned it for about 13 years. It has 4760 hours on it with no major problems until today. It has a onan 20 horse. I was running it today and it started to skip so i figured out which side and checked the spark which was fine then I noticed I had gas Coming back through the intake so I figured valve problems. Pulled head and noticed carbon hanging up valve. Looked into cylinder and noticed some scoring, Ive never rebuilt it and bought it with around 1000hours. I decided to rebuild it but when I called our local onan dealer he told me that motor is no longer in service >:( and parts are hard to come by. I guess what I am getting at is what are my options. Im thinking of upgrading motors, what do you guys recommend. I told my wife that I need to upgrade mills ;D, I dont no if she was to keen on that.

[coastlogger]

Carbon was almost certainly the prob. A bit of scoring is not a disaster. Id slap head back on, see how it runs, do a compression check to see how that is.It could run for years (or minutes) without further probs. You could pull piston to see if scoring has scuffed piston enough to cause rings to stick.You can probably get rings from an aftermarket supplier, once you know their exact size.
If head gasket is not too torn up and you are for economy, you could goo it up good with permatex and reuse.Itll go quite awhile usually.

[pineywoods]

Mark, swapping out the motor really isn't such a big deal. Woodmizer can supply you witha complete kit to upgrade to a kohler, Or if you are into do-it-yourself, there are several options. I swapped out my tired old 18 hp briggs for a 25 hp water cooled kawasaki. Was back sawing the next day. I love it. If you are considering buying a new engine, got to www.tulsa-engine-warehouse.com. They stock just about anything under 30 hp. Just watch the weight. Adding a heavier engine opens up a whole can of worms.

[Mark K]

I was thinking of swaping to a kohler so I went to woodmizers home page a minute ago. A little more then I thought but doable. I have a new thirty horse kubota that goes on a refer unit. I wonder how hard it would be to use that. I think the major problem would be making some sort of clutch. Ill have to look it over tomorrow. How hard was it to switch to the kawasaki.

[pineywoods]

I was thinking of swaping to a kohler so I went to woodmizers home page a minute ago. A little more then I thought but doable. I have a new thirty horse kubota that goes on a refer unit. I wonder how hard it would be to use that. I think the major problem would be making some sort of clutch. Ill have to look it over tomorrow. How hard was it to switch to the kawasaki.

The problem with the kubota will be weight. The motor mount, clutch linkage, head lift motor and gearbox, lift chains etc would need to be beefed up to support the extra 250 pounds of weight. The kaw weighs about 110 pounds complete with muffler and cooling system. click here
https://forestryforum.com/board/index.php/topic,22175.msg314829.html#msg314829

It's almost a bolt-on replacement. Drill 4 new holes in the motor mount plate to match the kawasaki, lower the belt guard about an inch, and re-route the throttle cables. The crank v-belt pulley might have to replaced or bored out.

[Mark K]

That motor looks easy to switch. I think im going to do a kohler motor.That way I might be able to be running again next week. I think i will take coastloggers advice and clean the valve and slap the head back on, maybe hone a little before to clean up scoring. Order a new setup and keep mine for a spare. I wonder why they discontinued these motors, never had no real problems with it, keep oil changed and air filter clean. That Kubota would be to heavy because mine only has that single 40 or 50 chain. It would require to many mods. Thanks for the help

[Chico]

I Personally wouldn't hone  it wouldn't hone it if you're noty going to change rings etc you'll prob start using oil esp if it's a little out of round . The rings have a wear pattern matching  the cyl now .Jmo

[pineywoods]

That motor looks easy to switch. 

Yeah, the lt 40 is a real easy mill to make changes to. Mine started life as a 95 manual, now it's about as much my creation as woodmizer's. Different motor, home built hydraulic turner, clamp, and toe roller, home-made auto-clutch, home-made remote control, sawdust blower.

[Mark K]

Chico-your probably right, I think im just going to take the top ridge off with the ridge reamer. It uses a little oil now but doesnt really smoke.

Pineywoods- Ive seen some of your add-ons in previous posts, looks like you do some great work. Looks better then alot of the professional welder fabricators around here. I would like to build a log turner on mine. This mill has pretty much become stationary. Just finished two weeks ago a 20' by 45' building for it. I was running it out of a barn. We ran a barn cleaner that takes the sawdust out. We left room to expand for an edger, the chain will pick the sawdust up from that to once in place.