Dolmar 5105 did not start - squirted oil into cylinder

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I have seen loos plugs do damage too because they pull heat away from the chamber head. They need solid contact to do that. Also itvcan lean it out if loose enough. But i think these real lean mix ratios combined with a not run in motor with some potential extra higher revs (lean) caused these failures. But a unfiltered opening into the engine near the carb would be a problem too. Sounds like it might a strato motor just described differently. Your plug wilk tell you how your mix is burning real quick good luck.
 
7sleeper said:
That is simply just plain not true! There is no "generally accepted rule..." and anyone trying to proclaim that is not living in reallity. I have never, and I am already been on this site for quite some time, seen any proof that one oil will break in better than any other!
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Ok, so im the first person that youve ever heard say that its recommended to break-in with conventional oil?? I live in reality dude and I think you need to relax a little. And also check my post 20 mins before yours where i said
cus_deluxe said:
there are no hard and fast rules for break in, and these days with better engineering and whatnot, a lot of new cars come from the factory with synthetic oil.
Click to expand...
 
cus_deluxe said:
Ok, so im the first person that youve ever heard say that its recommended to break-in with conventional oil?? I live in reality dude and I think you need to relax a little. And also check my post 20 mins before yours where i said
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Didn't mean to sound harsh, sorry if it came over that way!

And no you are not the first I have heard recomend break in oil, but that still doesn't make it any better. It is simply not neccesary in modern engines. In engines 20-30 years ago I would agree with you, but nothing in the last 20 years needs a break in oil. Well maybe some simple china clone engine(gas or diesel) might profit from a break in procedure but modern engine technology will not.

7
 
It was our only choice to export him, thankfully you guys took him... :crazy2::lol:

7
 
Re: carb settings -- it that something I can do? Or let the dealer do it? Supposedly on the 5105 they tuned when I first got it. But, as noted, it's got 3-4 gallons of gas through it now.
 
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.
 
This is getting old!!!

Lean oil mixtures.

441 piston..jpg WK441.jpg

Read!!!
http://www.klemmvintage.com/oils.htm

If you tune stupid rich, you may getaway with these lean mix ratios. They don't work with normal tuning!!!! Not only have I seen the failures, some other respected members and saw builders here have seen the same results.

Any questions???
 
Putting up an article about high-performance race dirtbikes and stuff has nothing to do with a dude with a stock 50cc saw cutting some firewood. None of my OPE has ever seen anything more than 70:1. and guess what they all still run, it must be magic! Ive said it a thousand times before, its all about the application. Telling a homeowner to go pay top dollar for oil and then say to run it 40:1 is silly. The guy with $2000 into his saw that gets taken to GTG's to cut cookies all day? sure put more oil in. Milling hardwood all day in the middle of the summer? sure. I really dont care about Klem and his motorcycles. If youre just gonna enter a thread and be a jerk then dont even bother dude.
 
The logic applies to every 2 cycle application. Running lean mix is at best like buying a high viscosity oil, putting it in your car and never changing the oil because it has high shear strength. If you read the article carefully you would understand this. These lean mixes do not work!! What do you mean by top dollar? any of the OEM oils work fine. You sound like someone from the lawnsite, or an oil rep, it wouldn't be the first time.
 
Well i cant help myself, i have to comment on this part of the oil thread. I believe alot of that article to be true on many levels. The rato/jetting and oil choice are crutial to the life of any motor in any application. I have seen first hand the differences of these ratios with. proper jettings effect on the internal parts of the motor. The same cr250 on the same track ran at 80:1 and tuned for it made it one day of racing. I tore it down to find alot of scuffing same motor rebuilt fully same brand parts and tollerances raced a full season at 32:1 and could have went longer. wether it be a saw a weedwopper a leaf blower pwc snowmobile and wether liquid cooled or air or even free air all have different needs for a given application. I truely believe i need to learn more on the topic but my tools and toys are living proof of proper oil choice with correct tuning/jetting for the given application give a long service life. I have learned a ton at the expence of top ends on stuff, but i learned how to find the cause of the failure not blame. Generally a gently used 2smoke can live at lean premix ratios but as soon as a long wfo pull it will show its evil face. Just because people have not had failures at 100:1 does not mean its good/ok maybe is because they still have enough laying in crank case to supplament the missing nessary oil for those long wfo pulls without a seizure. I have never pulled down my buddys stuff to see whst happens at abuse on 100:1. I do know my bikes got more oil the longer the strait aways were or where my rpms were going to be. Now a pwc sees heavy load all the time and drastic temp changes throughout the run but are set up much looser clearance to help with the changes. Also get different guality oil an a different ratio. I use many ratios for the same piece of equipment and many different jetting combos for the application. Saws are very close to the oil needs of a free air snowmobile raced in oval races where high rpms, high cyl temps, and high egts are presant which im my eyes would need a egd fd or fd oil at 25:1-32:1 to stay safe. Richer ratios jetted for the mix change provide more hp and longer service life. Then the required api tc or tcw3 oil it called for 40:1 stock for stock use. So better oil for high heat and more oil to keep alive for the application i used it for. In my group i have been able to keep motors together running many more hours then others thst followed mfg recs. They are nott always right. Testing and r&d. keeps us learning new things and hopefully ahead of the curve. Thank you. Sure i missed alotbof what i wanted to get accross to you all. Please take to heart atleast some of what i speak.
 
cus_deluxe said:
First, the generally accepted rule of thumb is to never "break-in" a saw (or any engine for that matter) on synthetic oil. its good to run dino-oil (conventional) for the first 3-4 gallons of fuel through the engine, which helps seat rings and mate the surfaces. Ive never heard of an engine burning up from running only synthetic from the beginning but its not great for it.
Click to expand...
This was indeed common knowledge, at least in 4 strokes. Any old flat tapped camshaft installation manual from the manufacturer would prove this.

I think the theory has been debunked over the years.
 
Very true and special oil with zinc to keep them going with aggressive lobes and high valve pressures/heavy springs. plus a precise breakin procedure. Without that they will not survive.period
 
update..

I pulled my muffler.

I viewed this video -

I may have a narrow score from the top of the piston about halfway down the piston on the exhaust side. It's not nearly as bad as the ones shown in the video for the bad pistons. It looks pretty similar to the one shown at 4:30.

My piston has a single ring.

The top exhaust edge of the piston is black. Maybe that is just normal carbon.

If scoring is much smaller than I could be missing it. If scores are .020" wide or .010" deep then I don't think I have any.

I can try to post some pics in a day or so.
 
Common, post those pics. Sounds like you toasted it with your 107:1 ratio. Education can be expensive at times, sorry for your loss.
 
coloradotrout said:
Yes Question -- what is this suppose to show me? Is that a picture of a good piston?
Click to expand...

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.

362 piston.jpg
 

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