Dolmar 5100s

[Bootlegger]

My Dolmar 5100s is now over two years old, three cutting seasons, and I have an awful time trying to start it after it has warmed up. Cold, it cranks right up. Warm, it coughs out some smoke but will stall. I wait 20-30 minutes, fires right back up. I've fooled around with the carb adjusters but it doesn't seem to do any good. Thoughts?

 

[smokinj]

sounds like an air or vaccum leak...I would check the carb boot and the bolts that hold the carb on may have just losen up..

 

[Bootlegger]

sounds like an air or vaccum leak...I would check the carb boot and the bolts that hold the carb on may have just losen up..

Hmmm, when its running full open it makes a very slight "huff-huff" sound that doesn't seem to affect the performance but is coming from that part of the saw. Would this be consistent with the vacuum leak or do I just need to clean the crud off my saw?

 

[Bigg_Redd]

My Dolmar 5100s is now over two years old, three cutting seasons, and I have an awful time trying to start it after it has warmed up. Cold, it cranks right up. Warm, it coughs out some smoke but will stall. I wait 20-30 minutes, fires right back up. I've fooled around with the carb adjusters but it doesn't seem to do any good. Thoughts?

In related news the MS290 that I've had for 7 or so years and which has had the air cleaner off only once continues to function flawlessly.

























Dolmar

 

[smokinj]

sounds like an air or vaccum leak...I would check the carb boot and the bolts that hold the carb on may have just losen up..

Hmmm, when its running full open it makes a very slight "huff-huff" sound that doesn't seem to affect the performance but is coming from that part of the saw. Would this be consistent with the vacuum leak or do I just need to clean the crud off my saw?

cleaning always good but I would take the air filter off and just check the bolts and see if there lose. that would be best case.

 

[kevin j]

Checking for air leaks is good first place, as the penalty for damage is great when running lean.

However, if it starts better cold than hot, (assuming not a heat related ignition issue) then it is probably too rich not lean.
What is your starting drill? They are sensitive to proper procedure. If you use any choke when starting hot it may be too rich.

 

[zzr7ky]

IIRC - For hot or warm start turn Choke On, then to Off, THEN Start. Something about setting a half throttle cam.

Mike

 

[WOODBUTCHER]

sounds like an air or vaccum leak...I would check the carb boot and the bolts that hold the carb on may have just losen up..

Hmmm, when its running full open it makes a very slight "huff-huff" sound that doesn't seem to affect the performance but is coming from that part of the saw. Would this be consistent with the vacuum leak or do I just need to clean the crud off my saw?

cleaning always good but I would take the air filter off and just check the bolts and see if there lose. that would be best case.

When did this problem start.....just recently?
New gas/mix ?
My 5100s is never hard to start.....gotta be something.


WoodButcher

 

[Bootlegger]

When did this problem start.....just recently?
New gas/mix ?
My 5100s is never hard to start.....gotta be something.


WoodButcher

Yes, recently. Gas mix is the same. Cold start is easy, one pull on choke, one pull on run and off it goes. Then when its warmed-up and I turn it off, on restart it will catch and sputter then die. I have to leave it for 20 minutes or so before I can restart it.

 

[Bootlegger]

My local Dolmar dealer replaced the plug. That's it. I feel foolish that this was the problem but I can't figure how the plug could cause the cold start/hot start problem.
But here's the proof.
Started with this 18' poplar.

Turned it off, got the camera and started in on this 12' chunk off a large maple that fell in last year's ice storm. Started on the second pull.

As I worked this big hunk of wood I had to turn off the saw several times to turn the log. It fired up on the first pull every time. I even got lazy and did a couple drop starts to save the back and test the saw.

The proof is in the test, all I needed was a new plug.

 

[smokinj]

If it works it works!

 

[Bootlegger]

If it works it works!

Indeed!

I'd still like to learn how to tune it though. Any tips that don't require I buy another tool?

 

[Singed Eyebrows]

Do you have both high & low adjusters on the carb? The low speed(if you have it) is set so that if you grab a handfull of throttle it responds quickly. The high speed is set so you have the fastest chain speed through the wood. If setting HS out of the wood the saw should not scream. If it is too lean you can hurt the piston. Randy, former Sachs Dolmar dealer

 

[Bootlegger]

Do you have both high & low adjusters on the carb? The low speed(if you have it) is set so that if you grab a handfull of throttle it responds quickly. The high speed is set so you have the fastest chain speed through the wood. If setting HS out of the wood the saw should not scream. If it is too lean you can hurt the piston. Randy, former Sachs Dolmar dealer

Yes, it has H and L, both turn 1/4 turn before they run into the limiters.

The saw "screams" when I crank the trigger out of the wood, inside of the wood it sounds ok.

Sometimes it hesitates at low idle when I "grab a handful of throttle" (you mean "finger" full right?). The hesitation is very brief.

 

[smokinj]

Do you have both high & low adjusters on the carb? The low speed(if you have it) is set so that if you grab a handfull of throttle it responds quickly. The high speed is set so you have the fastest chain speed through the wood. If setting HS out of the wood the saw should not scream. If it is too lean you can hurt the piston. Randy, former Sachs Dolmar dealer

Yes, it has H and L, both turn 1/4 turn before they run into the limiters.

The saw "screams" when I crank the trigger out of the wood, inside of the wood it sounds ok.

Sometimes it hesitates at low idle when I "grab a handful of throttle" (you mean "finger" full right?). The hesitation is very brief.

the way to tune a saw is wot on the h screw you can do it with a tach or by ear if your not tone death.You could also post a video and a lot of people could help...It sounds like your pretty good on the H side and need a little more on the L scew
http://web.archive.org/web/20051018212959/www.madsens1.com/sawtune.htm

 

[LLigetfa]

The saw "screams" when I crank the trigger out of the wood, inside of the wood it sounds ok.

Sometimes it hesitates at low idle when I "grab a handful of throttle" (you mean "finger" full right?). The hesitation is very brief.

If it screams on WOT no load, it's too lean. Richen up th H until it burbles (4 strokes). It will smooth out under load.

If the L is too lean, it will hesitate and bog when you give it a lot of trigger at once. Richen up the H to reduce the bogging.

 

[Bootlegger]

If it screams on WOT no load, it's too lean. Richen up th H until it burbles (4 strokes). It will smooth out under load.

If the L is too lean, it will hesitate and bog when you give it a lot of trigger at once. Richen up the H to reduce the bogging.

The limiters only allow a 1/4 turn and I've read they should be removed but I'm too much of a novice to permanently modify my saw like that. Any thoughts?

 

[Singed Eyebrows]

The saw "screams" when I crank the trigger out of the wood, inside of the wood it sounds ok.

Sometimes it hesitates at low idle when I "grab a handful of throttle" (you mean "finger" full right?). The hesitation is very brief.

If it screams on WOT no load, it's too lean. Richen up th H until it burbles (4 strokes). It will smooth out under load.

If the L is too lean, it will hesitate and bog when you give it a lot of trigger at once. Richen up the H to reduce the bogging.

Yep, Sounds like HS is lean. If you run out of adjustment because of the limiter I would look for a slight air leak. The listen for "scream" is subjective, the saw should not make a harsh scream & it's difficult to describe this over the internet. If this doesn't adjust out decently you might want to check the carb screen for plugging as well as put on a new gas filter, Randy

 

[Bootlegger]

The limiters only allow a quarter turn. The L was about halfway lean/rich. I turned it all the way rich, an eighth of a turn, and it ran perfect. It was the saw I bought two years ago and made quick work of some 12" maple logs I had laying around.

Thanks folks, y'all nailed it. Though I'm still not sure why changing the plug solved my hot/cold start problem. But its working now so the gift horse can keep his mouth closed.

There was some comments on other threads about the fuel mix and how that affects carb tuning. Factors like the ratio (40:1 or 50:1), ethanol, temp and altitude seem to affect it. So I'll raise a new query. I bought an oil additive called "Opti-2" that claims to be environmentally friendly by producing low smoke. While I care about my environment, the oil smoke from my 2-stroke is low on my priority list. However, not having to breathe burned oil while I'm using the saw is a big plus. This stuff makes no smoke and it is a more pleasant experience as a result. Anyone else use this stuff? Opinions?

 

[atvdave]

Great to see you got the problem worked out. I have had no issues with my 5100s and will remember your post just in-case I have issues. Thanks for the info..

In-fact just to day, I was cutting with my brother, and I was cutting 3 to his 1 cut's. But in his defense he was using a "wild thing", and some other cheap saw...

Dave

 

[Bootlegger]

Great to see you got the problem worked out. I have had no issues with my 5100s and will remember your post just in-case I have issues. Thanks for the info..

In-fact just to day, I was cutting with my brother, and I was cutting 3 to his 1 cut's. But in his defense he was using a "wild thing", and some other cheap saw...

Dave

I love my 5100s, but it is a "pro" saw which means it needs adjustment to maintain peak performance, or so folks keep telling me. So keep that saw tuned.