395xp won't start after milling - has it overheated?

[anynameyouwish]

Hello everyone!

I'm a bit stumped. Hoping someone can help with opinions as to what might be wrong with my saw, a 395xp. Running a 3-ft bar with skip tooth milling chain.

I was milling a long slab (23-ft),and towards the end, the saw leaned out, and ran out of fuel. OK, that happens with such a long cut (I take breaks for the saw's sake every 6-8 feet), so I stopped, let it cool for a few minutes, refueled, and restarted. Finished the cut, no problems.

Stopped the saw and tried to restart for the next slab, and it wouldn't start. Tried the throttle trick (keep throttle open whilst pulling, choke off), and it started, but then died abruptly in the middle of the cut (I think but cannot swear to it, that there was a bit of smoke coming out of the engine). Now it only starts when I keep the throttle open.

I've used this saw for two years for milling big wood and no problems.

The H jet is all the way open, as is the L.

Could I have burned up the saw? Maybe my 50:1 mix is missing some oil and it overheated?

What in the world could be happening?

 

[rupedoggy]

The H jet is out to the stop but not ALL the way open. I feel 50;1 milling is to lean on oil. Milling is one of the hardest things you can ask of a saw. Stop guessing and pull the muffler and look.

 

[Ridgehiker]

with the jets all the way open like you say, its not going to run any other way than throttle plates all the way open, i would try getting the jets screwed in some and really take a close look at your fuel, maybe contaminated with water.

 

[anynameyouwish]

The H jet is out to the stop but not ALL the way open. I feel 50;1 milling is to lean on oil. Milling is one of the hardest things you can ask of a saw. Stop guessing and pull the muffler and look.

Excellent suggestion. I did just that and it looks to me that the piston is scored. What do you think? This is the first time I've done this so I'm not sure what a scored piston looks like.

 

[sean donato]

Not the beat picture, but definatly looks like there's some scoring on the one side.

 

[singinwoodwackr]

Hello everyone!

I'm a bit stumped. Hoping someone can help with opinions as to what might be wrong with my saw, a 395xp. Running a 3-ft bar with skip tooth milling chain.

I was milling a long slab (23-ft),and towards the end, the saw leaned out, and ran out of fuel. OK, that happens with such a long cut (I take breaks for the saw's sake every 6-8 feet), so I stopped, let it cool for a few minutes, refueled, and restarted. Finished the cut, no problems.

Stopped the saw and tried to restart for the next slab, and it wouldn't start. Tried the throttle trick (keep throttle open whilst pulling, choke off), and it started, but then died abruptly in the middle of the cut (I think but cannot swear to it, that there was a bit of smoke coming out of the engine). Now it only starts when I keep the throttle open.

I've used this saw for two years for milling big wood and no problems.

The H jet is all the way open, as is the L.

Could I have burned up the saw? Maybe my 50:1 mix is missing some oil and it overheated?

What in the world could be happening?

I wouldn’t use 50:1 on any milling saw…

 

[ballisticdoughnut]

It’s definitely scored, your looking at a new top end on that saw. Cylinder mite be salvageable, only way to know is tear it down. Clean the transfer and see what the plating looks like. Gotta open up the high speed a bit and run 40:1 or 32:1 mix for milling. That’s really hard work even for the biggest saws on the market.

 

[Dennisthemenace]

Cooked, 50/1 and limiter caps and milling = bad news.

 

[anynameyouwish]

Cooked, 50/1 and limiter caps and milling = bad news.

Fair. This is the first time I've done such a long and hard cut. My previous strategy of staying within the limiters and using 50:1 has got to go. What RPM would you recommend if, I run, say, a 40:1 mix? I know you drop RPMs, but by how much?

I have a tach, BTW, and have played around with it, so should be good to tune.

 

[anynameyouwish]

What I'm seeing from some internet searching is that I should be running 32:1 or 40:1, with the carb at 1K below max rpms. Since max RPM for the 395xp is 12.5K, this means set it at 11.5K. Does this sound right?

 

[Lightning Performance]

What I'm seeing from some internet searching is that I should be running 32:1 or 40:1, with the carb at 1K below max rpms. Since max RPM for the 395xp is 12.5K, this means set it at 11.5K. Does this sound right?

Set hot after cutting not set cold. Many forget this bit and hurt pistons.
You need to post a decent pic to diagnose anything.

 

[anynameyouwish]

Set hot after cutting not set cold. Many forget this bit and hurt pistons.
You need to post a decent pic to diagnose anything.

Set at what? 11.5K?

 

[farmguywithasaw]

Excellent suggestion. I did just that and it looks to me that the piston is scored. What do you think? This is the first time I've done this so I'm not sure what a scored piston looks like.

 

[Lightning Performance]

Set at what? 11.5K?

I don't generally need a tach to set my max RPM. I will pull up mid cut milling or bucking to make adjustments. 10-11k RPMs is generally a safe spot on modern high-speed tools for milling long hard runs. I go fifteen minutes straight WOT on the ported 660 milling saws. Older stuff not so much. I've always tuned by ear and usually can be quite close to guessing a tach setting.

 

[sean donato]

Most don't use a tach to set rpm. Rather make it 4 stroke oit of the cut, but clean up in the cut. Milling you go a tad richer. Adding oil, (higher ratio) also slightly leans out the fuel present, since it is being replaced by the added oil. You'll need to retune for this anyway. Ditch the limiter caps all together, all they do is end in heartbreak since you can't actually tune the engine fully.

 

[LuDookie]

With the kind of work my 395 constantly does, long bars, big wood, and stumps… I always run it with 40:1 mix, and tuned right at 12,000 rpm. This has kept the piston in pristine looking condition and the saw always runs strong, no fear of overheating or scoring. In a milling situation I’ve heard even Husqy recommends a richer mixture for fuel. Also, I cringe when I start running out of fuel while working the saw hard. I try to avoid that. If you’ve been running 50:1, thinking your carb jets are wide open when they could have gone richer, for a couple years, that could have surely done it in. Sorry for the loss.

 

[LuDookie]

What I'm seeing from some internet searching is that I should be running 32:1 or 40:1, with the carb at 1K below max rpms. Since max RPM for the 395xp is 12.5K, this means set it at 11.5K. Does this sound right?

395’s run pretty decent from 11.5 to 12. I often just listen to my saws in the wood, making sure they burble from time to time when I lift them out of their load. I also check stuff with a tach from time to time, but whatever works.

 

[anynameyouwish]

With the kind of work my 395 constantly does, long bars, big wood, and stumps… I always run it with 40:1 mix, and tuned right at 12,000 rpm. This has kept the piston in pristine looking condition and the saw always runs strong, no fear of overheating or scoring. In a milling situation I’ve heard even Husqy recommends a richer mixture for fuel. Also, I cringe when I start running out of fuel while working the saw hard. I try to avoid that. If you’ve been running 50:1, thinking your carb jets are wide open when they could have gone richer, for a couple years, that could have surely done it in. Sorry for the loss.

Yeah, I got a new top end put in, and am now running 40:1 and tuned at around 12K. So far so good. I use an IR thermometer to monitor temps and my cylinder has never gone above 285 F since I made the change. Expensive lesson to learn but hopefully it'll never happen again.

A minor problem is that now I'm getting quite a bit of dribble out the cylinder (unburnt gas/oil) but that's OK. My saw now has a partially liquid-cooled engine!

 

[LuDookie]

Yeah, I got a new top end put in, and am now running 40:1 and tuned at around 12K. So far so good. I use an IR thermometer to monitor temps and my cylinder has never gone above 285 F since I made the change. Expensive lesson to learn but hopefully it'll never happen again.

A minor problem is that now I'm getting quite a bit of dribble out the cylinder (unburnt gas/oil) but that's OK. My saw now has a partially liquid-cooled engine!

Sometimes those hard lessons will make you born again. If we’re lucky, we get to learn from the mistakes of others.

 

[cookies]

Yeah, I got a new top end put in, and am now running 40:1 and tuned at around 12K. So far so good. I use an IR thermometer to monitor temps and my cylinder has never gone above 285 F since I made the change. Expensive lesson to learn but hopefully it'll never happen again.

A minor problem is that now I'm getting quite a bit of dribble out the cylinder (unburnt gas/oil) but that's OK. My saw now has a partially liquid-cooled engine!

Unburnt oil puddles in the crankcase when the saw is shut off, thats the puff of smoke you see when it is first started up. That excess oil is what keeps everything coated and protected from corrosion when the saw is off and stored, Protected when the saw is running from heat from friction. The 1/4 teaspoon or less of oil you see dribbling from the muffler is no real concern. Next up you need to look at modifying the muffler conservatively to further reduce heat and increase exhaust flow, the bonus is a hair more power and less oily mess from the muffler.