Any one blow up their Dolmar PS5100 yet?

[Max sawdust]

Update on replacement PS5100 saw:
Runs fine, using it for firewood and wood lot clean up.  Got to thinking, it could be that the failure on 30 foot ripping cuts could be the fact that the saw is a high RPM (14,500) saw, and ANY high RPM 50cc class saw would have a problem with big long ripping cuts.  With that said.. I went and bought a Husky 372XP for ripping laterals in log work.  (It is a proven saw for log work.)

The PS5100 is a fine general woodlot saw that has a couple of nicer features than the 346XP. (I like the sprocket and the fact that the 5100 runs 3/8 pitch chain instead of .325 chain)  I do feel the 346xp was more "even tempered" and started a little easier when some warmer than cold.  Again, for me dealer support  is important and I have a great dealer for the Dolmar.

[ladylake]

Any saw should be set richer for 30' ripping cuts including you 372

[SawTroll]

[RSteiner link=topic=33665.msg492554#msg492554 date=1226945469]


I have done a lot of brush clearing with my PS5100.  Actually for brush work I want a saw that will rev up quickly and cut the stems rather than pull the saw with a slower moving chain.  Last Saturday I helped a farmer friend cut brush and small trees along the edge of one of his fields.  I used the Dolmar for about 6 hours.  Rarely did the saw run at full throttle for any more than a couple of seconds on the small stuff.

I find it a great saw to use for both brush and larger trees.

Randy
[/quote][/size]

If you want fast accelleration, get the 346xp, it revs up much faster than the 5100 - but don't run it on part throttle - "blipping" is the right way on small twigs.     

[John Mc]

If you want fast accelleration, get the 346xp, it revs up much faster than the 5100 - but don't run it on part throttle - "blipping" is the right way on small twigs.     

Saw Troll -  I've heard that statement about not running part throttle a few times now. I do try to follow that recommendation. Just curious why that is. What does part throttle operation do to a saw? I assume it's got something to do with the mixture being incorrect at part throttle, but doesn't the reduced power output offer some protection?

Is it still a problem if you run part throttle when not under load? I've got one saw that's a bit cold blooded. In cold weather, when first started it dies if I let it come back to idle. If I run it at part throttle for a minute or so it's usually OK. I don't like to rev it way up when cold, but I'm wondering if this type of part throttle operation is a problem.

John Mc

[beenthere]

John Mc
I've a friend that I sometimes cut with, and he is a "part throttle" cutter. I often thought it was why he has so much clutch trouble. Seems at part throttle, the chain bites and catches a lot. Seems he doesn't have engine problems. Running a Stihl, 028.

[Tom]

I've been told that it is the chain speed that is important more than the engine RPM's.  The saw is designed to drive the chain at the proper RPM for efficiency.

Reving a chainsaw to its designed limits,unloaded,isn't supposed to hurt them.  As a matter of fact, it's a way to determine if the oiler is functioning properly.  Reving one to its designed limits, under load, is the proper way to use one.

I don't really know, just reiterating what I've heard.  I've always been more suspect of someone who continually "gooses" the throttle.  That can't be good on any engine.  I don't know why folks do it.  They do it with motorcycles too.  Most seem to have gotten away from the habit when driving cars and trucks, except for some drivers in big trucks.

[TexasTimbers]

I have a buddy who works for Clark Forklift who told me not to "work" my skid steer at low RPM's. Daid it was hard on the hydrostatic pump, among other engine vitals. Said it was cool to let it idle sitting, or to "half-idle traverse" as long as it isn't doing work or using hydraulics. Maybe putting a load on any type of combustion engine is not a good idea, under most circumstances.

I have never goosed my engines, but I sneak up behind my wife every now and then and goose her in the sides with my index fingers while simultaneously making a loud quacking sound. She pretends to dislike it, but i know it is just an act. The slaps to the cheek sting a little when they connect though.

One time she was taking out the Thanksgiving dinner. What I discovered was, if you goose the chick who is removing the turkey, you better duck or it could be your swan song.

I had to eat crow that year, and it was a very unpheasant experience.

[John Mc]

Where I got the mixture assumption from was hearing someone say that most chainsaws are set up to run with a good mixture at idle and at full throttle. They also claimed that in between those two extremes, the mixture could be off (too lean). It did not make a lot of sense to me, since I thought that was what a carb was for... blending fuel into the airstream in the right proportions, regardless of throttle setting. I figured maybe a chainsaw cab was just a little different - optimized for full throttle operation.

I was aware of the chain speed issue (always fun to watch someone in the level 1 Game of Logging class try to bore cut "carefully" at part throttle the first few times they do it. In this case, what they think is being careful is actually what's causing them problems).

John Mc

[pallis]

I bought a modded 5100 that had been run with a pipe for awhile, opened up the muffler, had to rebuild the carb and fool with the intake to make it quit leaking, but it was worth the effort.  I run 32/1 mix, in all my other saws, and this 5100 runs great, better than great.  I've never blown up or burned up a saw, and I hope this amazing little jewel doesn't change that.

[RSteiner]

The part throttle thing has me wondering just what "part throttle" is.  I bought my first chainsaw in 1976 a Mini-Mac 25 followed the next year by a Mac 10-10.  Since then there have been a couple of Stihl's, two Sachs Dolmars, and a couple of Husky's, and now the Dolmar 5100.

I have run all the saws basically the same way and have not "blown" one up, yet.  Some of them just plain wore out, especially the Mac's after about 5 or 6 years of moderate use.  One Dolmar had to be retired because parts were no longer available for the ignition.  The Stihl's and the Husky's are still in running condition.

That said, there are times when I run the throttle full open as well as there are times when I may run them with the throttle just under full open without bogging down or lugging the saw.  I think the problem with running at half throttle would be one of engine cooling as the flywheel is not moving as much air across the jug and the load on the saw would cause it to run hotter.  More RPM more air flow to cool the engine.

Just a theroy at this point. 

Randy

[cheyenne]

I have a Mac Pro 10-10 I still use and beat to death it just wont die. But by the end of the day I'm whipped. Takes two buds for my hands to stop shaking.....Cheyenne

[MakitaCS]

Takes two buds for my hands to stop shaking

That's what I'm talking bout homeboy, OG style!

So far my "AREA 51" is doing super bad ass.

It's a Grand National in disguise.

[Stutz]

Your 5100 may need the little metal carb boot ring installed, it helps form
a better seal between the carb and intake boot.
part # 181 131 020


I am no expert but I found this info helpful.

Adding extra oil. There are people who use more oil than what the
 50:1 ratio calls for. They think that they are doing their saw a favor by
giving it extra oil. This is not true! Too much oil is sometimes as harmful
as too little. Extra oil in the fuel reduces the octane rating of the fuel .
By running the saw with a richer A/F mix you are getting more oil in
to the motor, more fuel to cool it, negating the need to increase the
premix ratio.


Always adjust the carburetor properly rich. This helps
keep the saw from building excess RPM. It also reduces or
eliminates lean detonation which causes heat buildup in the
cylinder. Contrary to what many cutters believe, the saw
actually produces more horsepower when it is adjusted
properly rich. The saw won't scream like a "leaned out" one,
but it will make more stump power. Resist the temptation
to make it sound good.


A technical publication I got once stated that for every one percent
of gasohol, your engine runs 10 degrees hotter. That means a gas
blend with 10% gasohol causes the engine to run 100 degrees hotter.
This added heat along with a hotter burning, leaner mix can lead to
disaster too. Too much heat on the exhaust side creating a seizure
was becoming all too common.

[SawTroll]

....
That said, there are times when I run the throttle full open as well as there are times when I may run them with the throttle just under full open without bogging down or lugging the saw.  I think the problem with running at half throttle would be one of engine cooling as the flywheel is not moving as much air across the jug and the load on the saw would cause it to run hotter.  More RPM more air flow to cool the engine.

Just a theroy at this point. 

Randy

I believe it is mostly because most saw carbs have no "mid throttle" jet - the saws simply aren't meant to be run that way!