Siezed Engine--ProMac610 oops!!

[ChainsawChick]

I am a newbie chain saw user but have basic knowledge about 2 cycle engines. OK, you can shoot me now or later for this long, detailed but funny story. Once upon a time, there once was a girl in a land far, far away.........I had borrowed a Pro Mac610 with a 20 inch bar from a friend to cut up a HUGE Elm tree that I got for free on craigslist as well as some other wood that I picked up when the local Utilities came through the area and cut down a number of trees. My friend gave me a container of premixed gas which I believe was appx 30:1

Over the next several weeks another good friend of mine and a local day laborer with chainsaw/tree experience helped me cut up a bunch of the wood bit by bit. I had wanted to plow through a bunch of it since the project seemed to keep dragging on so we set aside a Sunday afternoon to cut the rest of the logs down to size so I could rent the wood splitter the following weekend. By this time we had used up the original can of gas and had mixed up several more by using the premeasured little plastic containers of oil to a gallon of gas. I didn't think through the entire process and thought that the 50:1 ratio was providing a richer mixture and not a leaner mixture, and besides the local guy said that it would be OK so I kept using the 50:1.

On this particular Sunday my friend and I worked for about 4-5 hours straight before seizing up the Pro Mac610. In retrospect, we analyzed that potentially the combination of the following contributed to the seizer--
1) slightly leaner gas/oil mixture
2) working the chainsaw 4-5 hours straight
3) the HUGE elm was especially dense/hard and had an extra large diameter for the bar length and saw

Wanting to fix or replace my other friends saw I found this site looking for some answers to either rebuild the seized engine or hunt for a deal on a used chainsaw. I read several awesome and helpful threads--differences and history of several chainsaw brands/models including the pro mac 610, the risks of buying used, buying used from pawn shops, gas/oil mixtures, and several others.

Meanwhile, my one buddy(who happened to be a farm boy from Nebraska who is kinda like MacGyver) suggested we empty out the gas/oil mixture and add Marvel Mystery Oil for a few days in hopes of potentially waving a magic wand over it before ripping it apart and rebuilding it.....so far no such luck.

While I was praying about the Marvel's working I happened to find the exact pro mac 610 at a local pawn shop for $125 and it started right up! In my search of used chain saws in Salt Lake City, I also saw several other of the comparable chainsaws that were talked about on the site including a husky rancher 55, some stihls(including one that had 311y on it that a bunch of you mentioned was often confused for a model number) and some others in the same price range. I was a bit overwhelmed with weighing out the options of replacing it with something other than what it was so I just applied the K.I.S.S. principle and bought the pro mac 610 for $125.

OK. back to the seized engine and my question....lol....is there anything else I should try before digging in and taking apart the engine to try to rebuild it with some replacement parts from some guy on ebay and/or this site and the help of my MacGyver friend in hopes of putting it back together to potentially have a chainsaw for myself now that I have replaced my buddies with a working one? Or should I just hand over both chainsaws to my buddy so that he now has one for parts in addition a working one, and should I just go pick up a decent used one for myself following all you guys advice from the other threads?

thanks in advance for any and all--help, advice, suggestions, stupid jokes, sarcasm, "you should have known better"s. etc.etc.

 

[ericjeeper]

I would give him the broke one too..

And offer to fix it.. He might have some family issues tied into that particular saw.
Some of us are wierd about that..
Then if you are foreseeing yourself needing a chainsaw again.. Go buy yourself one..
Cause I doubt he is going to loan you one again.. smiling here,,,
Never Loan a chainsaw has always been my motto.
But you are a good person you did fix it, or atleast replace it.. Most folks would have just brought it back and said "I do not know why it quit..when you get it fixed I need to use it again"
Happy Holidays.

 

[rb_in_va]

You should have replaced the PM610 with the 55 Rancher. He would probably be your bud for life. I would have at least asked him first. He might have hated that saw and split the cost of the Rancher. I don't know though. My dad loved his PM610, until he got his 262XP that is!

 

[mbopp]

I've got 2 of the Mac 610-design saws (Mac 655 & Monkey Wards 610 clone).

If you look at the economics, rebuilding the 610 will probably cost you more than the $125 you paid for the replacement saw. It's a 25 year old design, good for its time but far outclassed by newer saws. The Monkey Wards saw was given to me and had a scored piston & cylinder from a lean sieze. I found a parts saw on Evil Bay so I made one running saw out of the two of them.

If you don't fix it, your friend has a spare oil pump, bar & chain, carb & other small parts. If you want to salvage the saw, I'd try here for parts:

http://www.fayettevilleequipment.com/

 

[Kneejerk Bombas]

When you say it's seized, have you definately diagnosed the problem?
It would be real easy to pop off the muffler and look at the piston and cylinder. Maybe it's not as bad as you think.

 

[rb_in_va]

Meanwhile, my one buddy(who happened to be a farm boy from Nebraska who is kinda like MacGyver) suggested we empty out the gas/oil mixture and add Marvel Mystery Oil for a few days in hopes of potentially waving a magic wand over it before ripping it apart and rebuilding it.....so far no such luck.

MacGyver never needed no fancy Marvel Mystery Oil. He could build a bomb, fix a Jeep or a nuclear reactor with a paperclip and rubber band.

 

[Justsaws]

Pull the bottom plate off the saw and then pull the muffler. You are looking for scoring or "scratch" marks on the piston. The 610 is a very simple saw and easy to rebuild. It would be my opinion that the hardest part is the oil pump and you should not have to mess with that. If you have replaced his saw, return the broken one with it. Talk to your friend and then proceed.

I would think the reason the saw may have broke would be a dull chain. I own a lot of 610s and I have used then all day long with many different mix ratios. They are a good saw but overheat quickly with a dull chain. There is seldom just one reason for failure but rather a conspiracy of reasons.

I get the best results in terms of performance out of 32:1 in 610s.

Good luck.

 

[GASoline71]

Runnin' chainsaws for 4-5 hours straight is normal out here in the PNW. So it shouldn't have been a problem. I run my old Pro Mac 610 for hours on end some days. It just keeps comin' back for more. I run mine at 40:1. Runnin' it at 50:1 shouldn't have seized it. 40:1 is what the owners manual says to run. Stay away from the Marvel Mystery Oil, and stuff IMHO.

I know this is a stretch... but check your bar oiler. The PM610's oilers will fail at the diaphram. Then you will need to use the manual oiler a lot! Have you taken the bar and chain off the saw? If you over heat a bar and chain, it can lock up on ya. But then when it cools off should be moveable again. Just tryin' to cover all the bases.

Gary