Dolmar 5105 did not start - squirted oil into cylinder

[coloradotrout]

Common, post those pics. Sounds like you toasted it with your 107:1 ratio. Education can be expensive at times, sorry for your loss.

No that is not a pic of how a piston should look. The pis shows a piston that lacked proper lubrication, which created friction which = heat.

It doesn't sound like your saw is that damaged, pics will help determine that. Most of the time the cylinder will be reusable.

This is how a good, but well used piston should look.

View attachment 414863

Pulled out -- and cleaned up -- yeah? Mine in the cylinder is not quite so clean - oil drags along it, but I don't see those horizontal rings that I see in your photo.

 

[coloradotrout]

I did not get the pics, but had the right weather opportunity to go clear some hedge brush in the pasture. I added some oil - hoping to get close to that 50:1. Saw ran ok, but I did not have to work it very hard.

With the piston in -- peeping into the exhaust port -- it's pretty hard to say if there is scoring. The oil pulls up and down on the piston and makes it streaky which looks like scoring. There does appear to be one small scratch where there's bright metal showing.

 

[Haywire Haywood]

If it's one small scratch, it isn't hurt. Mix your stuff at 50:1 at least and find someone to properly tune it if you aren't confident. On the spark plug torque, there's no need to muscle it, but don't be afraid to tighten it either. If you're finding a good hand hold and leaning into it, you're overboard. Just tighten it.

 

[coloradotrout]

If it's one small scratch, it isn't hurt. Mix your stuff at 50:1 at least and find someone to properly tune it if you aren't confident. On the spark plug torque, there's no need to muscle it, but don't be afraid to tighten it either. If you're finding a good hand hold and leaning into it, you're overboard. Just tighten it.

Any idea what the plug torque should be (the manual does not say)?

I'm just using the wrench that came with the saw -- one end for plug, the other the bar. It's only about a 5" handle. But a stripped plug would be a real bummer.

 

[coloradotrout]

If it's one small scratch, it isn't hurt. Mix your stuff at 50:1 at least and find someone to properly tune it if you aren't confident. On the spark plug torque, there's no need to muscle it, but don't be afraid to tighten it either. If you're finding a good hand hold and leaning into it, you're overboard. Just tighten it.

The manual has a procedure for tuning. But I don't have a tach. What do I need for this saw?

 

[Haywire Haywood]

Just tighten it. No need to over think it.

 

[Ronaldo]

The manual has a procedure for tuning. But I don't have a tach. What do I need for this saw?

Go back to post #29 by cus_deluxe and read the thread that he referenced, tuning by ear in the wood is the best and most useful way to tune a saw.
Tighten the spark plug with your supplied tool (scrench) with medium amount of strength. Tightening it w/ all your strength using the scrench would be too tight.

 

[fordf150]

The manual has a procedure for tuning. But I don't have a tach. What do I need for this saw?

read this and watch all the videos then grab the little orange screw driver and go to town...you want to be on the rich side of things. lean is more power but also closer to seizing up if you go to lean.
continue using your opti2 oil but mix it at 50:1 at least.
2 fingers on the end of the scrench is good enough for the plug

http://www.arboristsite.com/community/threads/video-how-to-tune-a-chainsaw.113538/#post-1797089

 

[fordf150]

The manual has a procedure for tuning. But I don't have a tach. What do I need for this saw?

I would say if you dont have any experience doing it, then no dont mess with it. There are a lot of good videos on here, this thread is in blsnellings signature, he a site sponsor and a pro for sure: http://www.arboristsite.com/community/threads/chainsaw-tuning-101.250802/
Start here, but considering the reason for this thread, maybe find a friend who's done it before to help get ya going.

might as well read both threads

 

[Ronaldo]

read this and watch all the videos then grab the little orange screw driver and go to town...you want to be on the rich side of things. lean is more power but also closer to seizing up if you go to lean.
continue using your opti2 oil but mix it at 50:1 at least.
2 fingers on the end of the scrench is good enough for the plug

http://www.arboristsite.com/community/threads/video-how-to-tune-a-chainsaw.113538/#post-1797089

GREAT advice right here and covered all the bases!!!!

 

[coloradotrout]

I'm definitely going to 50:1 w/opti. That's simply 2x what's on the bottle. Makes it simple.

I'm reading up on the tuning.

I don't cut much firewood -- mostly brush clearing, fenceline clearing, and every now and then chop up one of those trees for the firepit. So I beat up my chain and bar pretty good. I clean out the bar and air filter, etc every 1-2 gas fills.

 

[sunfish]

Dang, this is unreal. Tighten the spark plug snug. Run 40:1 & learn to tune. These saws are known to be set lean from the factory. Sounds like your dealer doesn't know much either...

 

[coloradotrout]

Dang, this is unreal. Tighten the spark plug snug. Run 40:1 & learn to tune. These saws are known to be set lean from the factory. Sounds like your dealer doesn't know much either...

I'm still not sure why it died a week ago or so. I'm hoping it was just a loosen plug. There was a lot of compression loss, so that has me thinking it had to be something like that. I don't think I have much scoring, so plan to keep running it. I have to learn to tune. That video was OK, but being new to all this, still leaves me with questions. I know the dealer lowered the rpm on the 5105 that he replaced my burned-up 5100 with. I'm sure he's not going to tune like the fellow in the video. He'll just tach it to 12 or 12.5 on the bench.

I like tinkering with this -- got the NT chain sharpener and still learning on it.

 

[riley1056]

So much good info and some questions for me to answer:

The 5100 (blown) had very few tanks of gas - I'm going to say 2 or maybe 3. I went round and round with dealer and Dolmar. Finally dealer gave me the 5105 and pulled his Dolmar products off the shelf. They have not come back that I have seen. He has a few other brands of saws there now. One of the workers did mention something later about dropping the RPM might have helped". The 5100 had an exposed opening on the top of the carb as I recall. The 5105 has a foam piece covering that.

On the 5105 experience of late -- I now wonder if maybe my plug was loose? I had pulled it out awhile back and it looked good. I was not sure how tight to put it back in and did not want to strip. On Sunday when the saw died and would not start, I thought I heard air escaping on compression, but I could have been dreaming. Maybe pulling the plug -- adding 30wt to the cylinder -- and putting it back -- just sealed up the plug. The fact it started yesterday with all that 30wt burned up might be a good sign. When it died I just recall that pulling the rope had much less compression than usual.

How tight should the plug be? What in-lbs? or N-m probably in this case?

Ok -- so to pull the muffler -- just look for attaching screws and remove? How about looking into the plug opening?

FWIW -- I drained the existing gas in the saw, and added more opti to my remaining gas can and refilled the saw. I am using the 12 oz. bottle of opti that says it mixes ten gallons. I mixed one gallon at a time. On this last mix, my ratio was 1.2 oz. of oil to 1 gallon of gas or about 106:1. Until this last gallon I had been putting in 50% more oil so was putting in 1.8 oz of oil to 1 gallon or about 70:1. I'm going back to 70:1 at least. Maybe I should double the amount on the bottle which will be 2.4 oz per gallon or 53:1

I've put 3-4 gallons (not tanks) of gas through the 5105 using the 1.8 oz of opti to a gallon of gas (which looking at the little lines on the bottle is suppose to be 1.5 gallons of gas)

Just looking at the Opti website -- interesting that the 1 gallon pouches have 1.8 oz of oil, but the bottle I have has 12 oz and says 10 gallons. What is really interesting is the website *now* shows the "bottle" as having 13 oz of oil instead of the 12 oz bottle I have. 13 oz equates to 98:1, whereas the 12 oz was 107:1

Is 50:1 going to do any harm? Any downside? Because $2 per gallon vs $1 per gallon is really really cheap insurance.

Jesus is there a oil shortage in your area? I agree aimsoil will run and lubricate @50/1 on a water cooled cr250. But go get some maxima 927 and run 32/1 or at least some husky oil and run at least 50/1. Why risk it your going to burn up a 500 dollar saw trying to save a couple ounces of oil.

 

[sunfish]

I'm still not sure why it died a week ago or so. I'm hoping it was just a loosen plug. There was a lot of compression loss, so that has me thinking it had to be something like that. I don't think I have much scoring, so plan to keep running it. I have to learn to tune. That video was OK, but being new to all this, still leaves me with questions. I know the dealer lowered the rpm on the 5105 that he replaced my burned-up 5100 with. I'm sure he's not going to tune like the fellow in the video. He'll just tach it to 12 or 12.5 on the bench.

I like tinkering with this -- got the NT chain sharpener and still learning on it.

If it has any scoring, it will likely get worse and should be taken care of before it's run any more. A picture of the piston through the exhaust port posted here would be a huge help!!! Burning up the first saw should have been a sign that you were not using enough oil, and/or the saw was tuned too lean.

 

[riley1056]

Normally I don't lean towards oil being the problem but at 100/1 and 70/1 I almost guarantee it. If your dealer told you that was ok you need a new dealer and if he sold you the oil and said it was ok to mix it like that he should replace the saw.

 

[riley1056]

I feel bad for your situation and its really these damn oil manufactors faults. These ratios they are advertising are dumb and inexperienced people just read the bottle and assume it has to be ok. A water cooled engine running 160-180 degrees can live on less oil then a air cooled engine running @ much higher temps. Even then anything over 50/1 is just dumb. Your car will run on 1 quart of oil too but there's no reason to do it.

 

[coloradotrout]

Normally I don't lean towards oil being the problem but at 100/1 and 70/1 I almost guarantee it. If your dealer told you that was ok you need a new dealer and if he sold you the oil and said it was ok to mix it like that he should replace the saw.

Yes, the dealer said running opti at 1.2oz per gallon of gas in the 5100 was fine and said it was not the cause. He said Dolmar had a design flaw. I called Dolmar and Opti and wrestled this until the dealer gave me a 5105. He did tune it slower, but never suggested changing the oil ratio. Dolmar's ratio was 50:1. Opti's was 106:1 (12oz bottle used for 10 gallons). I used 50% more oil for all but my last mix, so 128oz : 1.8oz or about 71:1

 

[coloradotrout]

Yes, the dealer said running opti at 1.2oz per gallon of gas in the 5100 was fine and said it was not the cause. He said Dolmar had a design flaw. I called Dolmar and Opti and wrestled this until the dealer gave me a 5105. He did tune it slower, but never suggested changing the oil ratio. Dolmar's ratio was 50:1. Opti's was 106:1 (12oz bottle used for 10 gallons). I used 50% more oil for all but my last mix, so 128oz : 1.8oz or about 71:1

From here out, I'm mixing double the Opti, or 128:2.4 or 53:1

 

[coloradotrout]

If it has any scoring, it will likely get worse and should be taken care of before it's run any more. A picture of the piston through the exhaust port posted here would be a huge help!!! Burning up the first saw should have been a sign that you were not using enough oil, and/or the saw was tuned too lean.

I will get the pic. I tried, but getting a camera in that close was tricky. There is also some oil sliding around on the piston so it does look streaky, but those streaks change depending where you stop the piston, etc.