Mccullouch Mac Pro 700 - Fuel Tank

[Rolltide73]

Good Morning All,

I am new to the site... My dad bought a Mc Pro 700 in 1976 and has always taken good care of it. Last year, he had a few trees he needed to cut down, but when he finished he forgot to drain the fuel tank. (gas with 10% ethanol) We now have a place we can purchase 100% gasoline... which we use in everything now. Anyway, he remembered the other day that he forgot to drain it, and when he opened the gas tank lid, there was jelly everywhere. He was not looking to invest the time and money into fixing the saw, so instead he passed this treasure down to me... I've always wanted the saw anyway because of all the childhood memories we had together using this saw growing up. The saw really is in great condition and has not been abused.. just normal use now and then. The recoil spring was very weak and it needed a new pull string as the old one had broken before and was too short for me. So after finding Randy's Repair on Ebay, I ordered a new Fuel line w/ filter and a recoil spring. After some trial and error, I got the recoil spring in and working great....

So now, to the point... I pulled the top half of the gas tank off, only to realize that there wasnt just "jelly" in the tank... the paint was also peeling off the whole inside of the tank. I started with some carb cleaner and rags working for a few hours and got most of it out. The CORK gasket is shot.. and there is a black gasket that is also shot that goes around the back area that houses the carb. Do I HAVE to replace with a CORK gasket? Where can I get one? I looked around and found a thread about using Seal-All verses other products etc. but there was a lot of back and forth about this and that product... And the second part of my question is, would you just try and get the rest of the paint out and leave it bare metal?

Thanks for any help you can give... I am attaching some pictures as well. I got most of the jelly out before I pulled the tank and took some pictures. The last picture isnt me finished cleaning it, i just ran out of time.

 

[AVB]

The bad news here that your not going to find new parts for this saw. The company that made the saw is no longer in business. I wish weren't as I got 2 saws myself that I had to retire due no parts available for them. I did a Google for the cork gasket I could find any listing that is up to date.

Parts list can be found here http://www.searspartsdirect.com/partsdirect/part-model/mc-culloch-parts/all-products-parts/model-promac700model60011604/0684/1503200

The only options left is to make your own gasket or use fuel resistant sealer.

 

[Rolltide73]

Oh well, I will try some Seal-All and let it sit for a few days just to be safe. Maybe even try to use some gasket material plus the seal all.

Thanks for the quick reply. I'm sure I'll have more questions down the road.

 

[joe25DA]

Nice saw! Try permatex moto seal. Its fuel resistant and ive used it on cylinder bases and carb gaskets.
And don't worry, they made a ton of pm saws so there's plenty of parts saws and still many used and nos parts out there

 

[Rolltide73]

Thanks Joe. He has always taken care of everything he has ever owned, just a busy season in life and it was overlooked. He was originally going to sell it... I just couldn't let him do it though. It brings back so many memories that you just can't put a price tag on.

 

[naturelover]

If you have a scanner-printer, you might try scanning the bottom of the top of the tank to get an outline of it, cut it out and then lay it on some rubberized cork gasket paper.

I was fortunate enough that my gasket was in good enough shape to lay down on my scanner and print out a copy of it. Worked well for my 10-10s.


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[Rolltide73]

Thanks for the info... Just FYI, I called Randy's Engine Repair on Ebay. These guys have excellent service... and they had the OEM cork gasket in stock. $14.00 shipped and i should have it in about 2 days.

 

[Rolltide73]

Alright, so I got my gasket in the tank and everything put back together. Filled it up with some fuel and nothing... I can shoot some starting fluid in it and it will hit, but it's not getting any fuel from the tank. I pulled the gas line off the carb, and its completely dry. I'm thinking that the carb is stopped up and so there is no vacuum pulling the fuel from the tank? What do you guys think? Any thoughts? I have an exploded view of the carb as well.

 

[struggle]

DO NOT USE STARTING FLUID EVER on a two stroke engine. It removes all lubrication from the engine.

That said you will need to clean carb and install new gasket fuel pump kit in the carb.

 

[Rolltide73]

Thanks for the reply. I thought about that, but it makes it difficult when you're trying to diagnose a problem. I figured that just a shot of it wouldn't hurt.... just to make sure that it everything else was working like it should.
If I'm understanding correctly, I need to get a fuel pump kit for that Walbro Carb and thats it? It will come with a new gasket and everything else I need?

 

[redfin]

I'm glad you started this thread. I second the reply of NOT using starting fluid in the carb, I just put some mix in a clean spray bottle and spray into the throat.

I do have a question for the Mac gurus. I have a 1-42 in which the tank gasket is leaking. I have pondered using yamabond4 to seal it. Am I way off base thinking this?

 

[struggle]

Yes a carb kit will have the fuel pump in it along with other various parts including gaskets and needle valve etc. Pay close attention the placement of the gaskets and the depth of the metering needle valve if you replace it.

Find a small bottle like a couple oz. with a tip on it and use that for squirting some mix fuel down the carb to start test. Starting fluid even in small amounts can cause damage. Best to never use it ever on 2 stroke

 

[heimannm]

There are many, many options for McParts yet today in spite of the fact the original company sold the business a long while back.

Bret - Since the fuel tank and probably the fuel line were affected, you should replace the fuel line and filter while you are at it. Again a lot of choices for fuel line (just check e-bay) but Randy will have what you need though his prices are often a bit high. That said, $14 for the gasket is not bad, those cork gaskets are rather scarce today.

John - check your saw carefully to determine the source of the leak. If it is simply the gasket there are plenty of options from NOS to make your own. Be sure to "flatten" both pieces before you put it together or the gasket may not seal. I use a granite plate with a sheet of emery paper to make sure both pieces are truly flat. If the parts are truly flat you will not need any sealer but any of the fuel proof products like Three Bond or Yamabond will work.

On those older saws there is always the real possibility that oxidation over the years has corroded a hole through the tank. You can make a repair using JB weld or replace the parts if you want to make it go again.

Mark

 

[redfin]

Thanks

 

[Rolltide73]

Hey Mark,

I posted in the original post that I had ordered a new fuel line and filter from Randy's Engine repair... When I pulled it out, the line and filter were both trash. but thank you for the suggestion! I need all the help I can get.

Unfortunately, I put the new cork gasket in and tightened everything back down, and over the last two days, I have noticed a slight leak in one of the corners of the tank. So, I guess I will pull it back off and put some kind of sealer on with the gasket.

I am not very skilled in placing the metering needles where they should be etc.... Would it be better for me to order a new carb for the saw and then just have to worry about adjusting the idle, etc?

 

[heimannm]

There is no really simple answer. Rebuilding a carburetor and making it work is normally a pretty simple task but is there is some hidden fault, it could be very intensive to track it down and resolve it.

If you go the replacement route, consider this:

http://www.ebay.com/itm/NEW-McCullo...770?pt=LH_DefaultDomain_0&hash=item1c3c335a92

Mark

P.S. Another thought, you are in Alabama so try to connect with JoeyMT33 and your problems will be over.

 

[Rolltide73]

Thanks for all of you help. It is very much appreciated. I will try to get in touch with Joey.... Yall have a great weekend.

 

[fossil]

Walbro has a good download for the SDC carb that may help you out.

www.walbro.com/media/21892/SDCseries.pdf

You should be able to get a carb kit at any on line small engine supply house or maybe at a dealer near you.



‎

 

[naturelover]

Don't know if it's the same, but in order to get either of my parts carbs to work on the Mac 10-10, (sdc 44's), I had to set the metering needle level with the carb body instead of the tabs.


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[djones]

Napa carries the carb kits for the Walbro carbs. I order a couple at a time.