Compression only 40lbs

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thesnowsnake

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I had a Sachs Dolmar 116 given to me by a (FRIEND????) and it refuses to run.
I grabbed the plug and yes there is spark. the plug looks ok. but the compression is only 40 lbs cold pull. Any ideas.........Help need to cut my backyard up..


Don
 
I don't know, but I played with my compression tester the other day, and here were my results. A 7900 with new jug and piston was 120 psi cold, before it's first time cranked. An old Olympyk 355 that has been used and abused read 155 psi cold. A 951 Olympyk was 160 cold. A fairly new Solo 650 was 100. My guess is that 40 psi is much too low, though I do have an old Homelite 330 that will start and idol with low compression. I've seen a lot of jugs and piston kits on Ebay. Good Luck!

Pat
 
Generally upwards of 100psi is required to run. 40 psi is very low, and likely the piston, rings and cylinder are shot, with other collateral damage possibly incurred. There is also likely a reason why the top end is toast, like air leaks which needs to repaired or ruled out to ensure the life of the rebuild. A piston, rings and cylinder with the associated gaskets should be available, but you will spend a bit ($200 to $400 possibly) new for the needed parts. Others can confirm the actual cost. If you could find a good parts saw, you may be able to salvage the needed parts for less. I would expect you are going to be waiting a minimum of a 2 to 3 weeks to trim that backyard, if you get the parts headed your way soon, by the time it is reassembled, tested, and ready to do the work.
 
Thanks a ton guys. Its hard to guess what to do. but we have a Princess Auto here that sells factory rebuilt Poulen saws without bar for 99.00 beaver bucks. So may be this will be a parts saw.... Any takers hmmmmmm
 
That 116 will be a much better saw than the Poulan. Personally I would rather take the $150 you will spend getting the Poulan powerhead and a bar and chain and put it into parts to rebuild the Dolmar. The cost shouldn't be too much more, but you will get a vastly better saw. It depends upon your wants and needs, the Poulan is a cheap homeowner grade saw, whereas the Dolmar is a professional grade saw. If you only need a saw for this one project, or for very limited use, the Poulan may be the better buy. If you intend to use it more, or if the wood is over 8-10", then the Dolmar will be a much better saw, and rebuilding it will be a better option. The Poulan isn't suited for large wood or heavy use. Many have used them for significant amounts of use and had good luck, but they are less than an ideal choice.

In my last post I also forgot to tell you that if you pull the muffler and look into the cylinder through the exhaust port, you will be able to tell more on the condition of the cylinder and piston. They are likely scarred up from a seizure, but there is a chance that they are fine and the rings are simply stuck. This would only require a new base gasket some time, and a little solvent to correct if it was the case.

Even if you decide not to rebuild the saw, someone here may be interested in buying it for a rebuild or parts as well.
 
thesnowsnake said:
I had a Sachs Dolmar 116 given to me by a (FRIEND????) and it refuses to run.
I grabbed the plug and yes there is spark. the plug looks ok. but the compression is only 40 lbs cold pull. Any ideas.........Help need to cut my backyard up..


Don
I take it you were using a two stroke compression tester and not a four stroke ?
 
You're gonna have to elaborate on the compression tester "knowing" or "caring" about the design of the engine. Cylinder pressure is cylinder pressure whether it comes form a 2 cycle, 4 cycle, or 5 cycle (miller cycle engine, look it up) engine.
 
Hell I knew I did something wrong the saw is Orange and the tester was Black ship anyone know where I can get a small orange chainsaw compression tester that measures in cords.
 
sedanman said:
You're gonna have to elaborate on the compression tester "knowing" or "caring" about the design of the engine. Cylinder pressure is cylinder pressure whether it comes form a 2 cycle, 4 cycle, or 5 cycle (miller cycle engine, look it up) engine.




For all you who think I am kidding the 2 stroke tester has a short hose the 4 stroke has a long hose.
 
And the difference would be what? The extra volume of air in the longer hose means you have to pull the rope what.......................one extra time?
 
Hey you idiots can do what every you want I was just tring to help.I think more than one extra pull would be required, Put what would I know I just work on them???????
 
What would I know either? 20 years as an auto mechanic, ASE certified, Chrysler gold Certified, Stihl silver certified (you know them don't you....they make all those 2 cycle engines), degree in auto mechanics, MENSA member (documented IQ of 146). Bad form to call one an idiot.
 
Hey Paul you have alluded to that Mensa stuff before. Could you show us a copy of your membership card? I have trouble with this because:
1. Mensa member usually don't brag on their IQ.
2. Very few Mensa members are auto mechanics.
3. They seldom spend much time on chain saw forums.
4. They may be good rib cooks. I don't know about that one.
5. They generally have very high grammar and spelling abilities and you have not shown that in your posts.
 
sedanman said:
What would I know either? 20 years as an auto mechanic, ASE certified, Chrysler gold Certified, Stihl silver certified (you know them don't you....they make all those 2 cycle engines), degree in auto mechanics, MENSA member (documented IQ of 146). Bad form to call one an idiot.
Looks like you can't decide what you think you are. 20 years in auto when did you decide to be stihl certifed. Maybe that is why stihl can't get a 2 stroke to pass epa specs with out going to the 2-4 stroke engines. If you look at the Mac tool site you will see the short hose in the kit do you think that is just for tight spots?
 
From the mensa site: http://www.mensa.org/index0.php?page=10&PHPSESSID=c934b7c51aaf91f2d06c5824edb31724


"What kind of people are Members of Mensa?

There is simply no one prevailing characteristic of Mensa members other than high IQ. There are Mensans for whom Mensa provides a sense of family, and others for whom it is a casual social activity. There have been many marriages made in Mensa, but for many people, it is simply a stimulating opportunity for the mind. Most Mensans have a good sense of humor, and they like to talk. And, usually, they have a lot to say.

Mensans range in age from 4 to 94, but most are between 20 and 60. In education they range from preschoolers to high school dropouts to people with multiple doctorates. There are Mensans on welfare and Mensans who are millionaires. As far as occupations, the range is staggering. Mensa has professors and truck drivers, scientists and firefighters, computer programmers and farmers, artists, military people, musicians, laborers, police officers, glassblowers--the diverse list goes on and on. There are famous Mensans and prize-winning Mensans, but there are many whose names you wouldn't know."

IQ is the measure of intellegence not the depth of the well of ones knowledge (or their language skills) . Intellegence is the practical application of knowledge. The person with the higher IQ is more likely to be able to "think on their feet". 2% of the population qualifies for membership to Mensa with 6,437 members, Arboristsite has 128 potential mensans.
After "20 years in auto" I became Stihl certified as an additional diversion, I have not given up working on cars.
And when did this become an attack on Stihl, WTF does their emissions strategy have anything to do with my compression tester, stay on topic please.
Rupe, PM me your address and I'll mail you a photo-copy of my credentials. And oh by the way, you might be one of the 128!
 
Okay, okay, already. Can I use a short, fat hose or does it need to be a short thin hose? Does the shortness of the hose have to do with the time it takes for air to travel from point A to point B or is it strictly a volume kind of deal? Does it make a difference if I pull the cord fast or pull the cord slow. I don't mean to apply any pressure here or maybe I do. Do I? Mind you, I'm only a mechanic because I'm cheap, and I'm cheap because I'm broke, and, unlike some, I don't have an IQ high enough to measure, so help me out. I'm stuck. What is compression anyway? Honestly, no pressure is intended here, just questions. Unless, of course, you guys don't want to answer. Then forget I mentioned it.
 

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