455 rancher issues.

[Jason628]

So... I haven't messed around with many of these huskys but, I got handed a rancher 455 and got told to fix it. Saw idles well but when you chop the throttle it bogs. Owner tried putting a different carb on it and same issue. It has the EPA adjustment locks so the high and low will only move about 1/2 a turn. I turned the high out as far as I could and it runs a little better but, high rpm it kinda hunts up and down and will not completely ring out. Compression is around 120psi... which isn't great. I'm not sure what these usually run... 150? Any input would be appreciated. I'm bout ready to tell him it's a lost cause and needs rebuilt.

 

[Canadian farm boy]

Pull the muffler and check the piston.

 

[Jason628]

Lots of carbon. Other than that she looks ok

 

[Canadian farm boy]

Looks like the ring might be stuck. I’ve seen this on a couple of 455 ranchers.
Can you gently push on the ring through the exhaust port and see it move a little?

 

[Jason628]

Looks like the ring might be stuck. I’ve seen this on a couple of 455 ranchers.
Can you gently push on the ring through the exhaust port and see it move a little?

I'll play with it tomorrow when I get home. I cleaned on this thing for a while. It was very packed full of sawdust and grease. Looks like there is a lot of carbon on that piston. Ring could be stuck from carbon deposits. No scary looking score marks that I can see.

 

[Jason628]

Ring does not appear to be stuck. Sprayed some wd in there anyway. Thinking about removing the limiters for the high and low and see if I can get it running better. Seems to start and idle good.

 

[Nutball]

I wonder what seafoam would do to it?

 

[Jason628]

I wonder what seafoam would do to it?

It is like a solvent. I may try that if I still have some laying around. I've ran it in a few vehicles by pouring it down the intake while it is running. They always seem to run better afterward. Project farm on YouTube probably already tested seafoam on a Briggs. The 455 seemed to respond to the high being turned out as far as I can move it with the limiters. If you chopped the throttle it would bog and you kinda had to fiddle with the throttle to get it to Rev. With the screw out you could chop the throttle pretty hard and it would Rev but, not near as clean as it should be. I think if I had another 1/2 turn out on the high it would clean up.

 

[Jason628]

After seafoam. Ran it and went down to 100psi. Don't totally trust my comp gauge.

 

[Nutball]

But how clean does it look inside?

 

[Jason628]

But how clean does it look inside?

Significantly cleaner. That is probably the most carbon I've seen in a saw. Can see the top of piston in places. I was revving it and chunks of crap were flying out of the exhaust. Turned the high out another half a turn and I can't get it to bog anymore. I cut a few small logs with it and so far no issue other than it is as dull as a butter knife. I'll take it up wood cutting and make sure she is going to run okay before I give it back. Might even sharpen it if I can find the time.
Dude from project farm had good results with his test of seafoam. Pretty impressive results with his decrepit ford ranger. I've used it in my Mazda engines that have issues with valve lash adjusters and it's seemed to do the trick except for when I was having oil pressure issues due to failing rod bearings.

 

[FergusonTO35]

Do whatever it takes to get the carb limiters off and see if more high speed adjustment helps. Never assume that a new carb is set up properly from the factory, or that it will necessarily run right with limiters installed. Every two stroke engine is practically a law unto itself!

 

[Jason628]

Do whatever it takes to get the carb limiters off and see if more high speed adjustment helps. Never assume that a new carb is set up properly from the factory, or that it will necessarily run right with limiters installed. Every two stroke engine is practically a law unto itself!

Yeah they were a lot easier to get off than I thought they were going to be. I turned the high out and got her to rev. Saw is kinda tired so we'll see how long she lasts. Was packed full of crap. Wouldn't be surprised if it had overheated the cylinder.