HELP! 462 won’t rev up

[Stump Shot]

I don’t think so. It’s computer code *s-word I believe. Had a 572 that would start and idle like it was in the choke position on at3. Pull the throttle and it would not rev up at all, could hear the air being sucked through the carburetor, but no change in TPMs. Put a new coil on it and it ran fine

Maybe someday, someone would come up with a relatively simple to use diagnostic tool to check these type of things out, like in the automotive repair industry for example.

 

[huskihl]

Maybe someday, someone would come up with a relatively simple to use diagnostic tool to check these type of things out, like in the automotive repair industry for example.

There’s a guy in the Facebook groups looking for a MDG1 to try and reverse engineer it. Seems stupid that it’s not available to the public anyway. I guess breaking a law that isn’t enforced isn’t breaking the law

 

[pbillyi69]

this is why cpu chips shouldnt on a fuggin saw in the first place. they only serve to keep authorized repair shops being they only way to update firmware and diagnose issues

 

[Lions fan]

this is why cpu chips shouldnt on a fuggin saw in the first place. they only serve to keep authorized repair shops being they only way to update firmware and diagnose issues

Nothing to worry about, plenty of options out there if you don't like m-tronic saws.

 

[Coupe]

If you have a vacuum tester pull the tank filter out and take it off and plug a vacuum tester on
and see if it will hold pressure and if not check fuel lines and give that carb a really good clean and a new kit.
If that does not solve the problem you may have to give the coil a check to make sure it is not breaking
down.

 

[furb]

If you have a vacuum tester pull the tank filter out and take it off and plug a vacuum tester on
and see if it will hold pressure and if not check fuel lines and give that carb a really good clean and a new kit.
If that does not solve the problem you may have to give the coil a check to make sure it is not breaking
down.

Leave it hooked to the carb and pull vacuum?

 

[furb]

Carb holds vacuum through the fuel line, carb rebuilt, new air filter. Still acts the same, swapped solenoid from green to black to green again, new fuel filter. No change.

 

[cuinrearview]

I’d go Kevin’s route now. Dude ain’t sling blade but he’s just as savvy with a saw.

 

[furb]

I’d go Kevin’s route now. Dude ain’t sling blade but he’s just as savvy with a saw.

I only thought about checking the wires after it was back together. I’m going to see a guy with a pile of parts saws tomorrow and hopefully he has a smashed 462 to grab parts from. He has the 362 stuff I need he thinks but won’t check so it’s an hour long drive that’s a gamble. It almost acts like it’s limited the rpm’s and then flooding itself out.

 

[furb]

I only thought about checking the wires after it was back together. I’m going to see a guy with a pile of parts saws tomorrow and hopefully he has a smashed 462 to grab parts from. He has the 362 stuff I need he thinks but won’t check so it’s an hour long drive that’s a gamble. It almost acts like it’s limited the rpm’s and then flooding itself out.

No 462 stuff, not much 362 stuff. The business is changing hands and the stash is dwindling

 

[lehman live edge slab]

No 462 stuff, not much 362 stuff. The business is changing hands and the stash is dwindling

I’d say it’s the coil that’s giving you issues personally, controls fuel map and timing

 

[furb]

I’d say it’s the coil that’s giving you issues personally, controls fuel map and timing

I’ll order one. Got the 362 together and now that won’t run right…

 

[furb]

So I bought a locked up parts saw. While swapping the coil I found the intake boot clamp was loose. I can’t believe I didn’t catch it but with the new coil it runs. Probably that clamp was the whole problem.

 

[hacskaroly]

While swapping the coil I found the intake boot clamp was loose.

Those intake boots can be a pain in the rear. I was working on a buddy's MS 311 and ended up chasing my tail trying to figure out what was going on with it...ended up being the intake boot! The smallest little crack or tear can be hard to find, but the saw knows not to run correctly because of it!

 

[furb]

Those intake boots can be a pain in the rear. I was working on a buddy's MS 311 and ended up chasing my tail trying to figure out what was going on with it...ended up being the intake boot! The smallest little crack or tear can be hard to find, but the saw knows not to run correctly because of it!

I must’ve thought I went over this but it was the 362 or something. I know better than this but multiple saws in pieces at once while the shop is a mess is bad news. Those boots are $88 now I think.

 

[mbret2004]

Picked up a 462, starts and idles but won’t rev up. It’s getting fuel, spark screen is clean, new plug, no air filter but it doesn’t look like it was run without. Is it worth throwing a carb at it? I don’t have access to plug this in. I do have solenoids off of 261s that might swap over. Carbs are $150 for a new take off

If that saw is new, let the dealer fix it.

 

[furb]

If that saw is new, let the dealer fix it.

It’s a used tree service saw that had someone trying to fix it that made a mess of all the saws I got from him

 

[mbret2004]

I didn’t really. Don’t actually know if it can be diagnosed without the SDS software. The brain is in the coil. Many of the issues we associate with fuel problems are actually issues with the coil communicating to the carburetor.
My main gig is port work, not repair. Rather than spend hours or sometimes parts of multiple days trying to diagnose something, it’s often easier for me to replace a carburetor or coil and try it. I have ended up purchasing a few new carburetors that didn’t fix the issue and then replacing the coil in the end. Still sitting on a couple brand new carburetors because of it.

I feel the frustration, been there, have spare carbs to prove it too!

 

[mbret2004]

It’s a used tree service saw that had someone trying to fix it that made a mess of all the saws I got from him

Ok, too bad.

 

[sawmikaze]

I had a 462 that wouldn't rev up to max RPM. best way I can describe it was that it felt like it was in some kind of rich mode and wouldn't rev past around 10 grand and a solenoid and wiring harness didn't fix it. A new coil did.