Hello...Pro Mac 55

[a. palmer jr.]

I've been looking for an expert on these chain saws. I have an old Pro Mac 55, that I got from my Father years ago, and I know very little about. The saw hasn't been run in at least 30 years, and is difficult to start and keep running. It has a Walbro SDC Carburetor which is marked 7-74 49, which I assume is a date and a carburetor version. From this forum I've learned that it has a fixed high speed jet like the one in the photo posted earlier in the thread. I have a few questions about this saw.

1. Is K10-SDC. the correct carb kit for this carburetor?
2. Is it ever necessary to change the fixed jet to run better on the crappy gas we get these days
3. What is the procedure for adjusting the needle valve?
4. I'm assuming I should also order a new fuel line and filter?
5. There appears to be a small filter inside of the brass fixed jet. Does this need to be replaced?

Any more pointers about this saw? According to this forum, the Pro Mac 55 seems to be a popular saw.
Thanks in advance for your advise.

One suggestion I'd have is to buy something other than crappy fuel. Good fuel is out there, just have to look a little harder for it.

 

[brandonstc6]

I've been looking for an expert on these chain saws. I have an old Pro Mac 55, that I got from my Father years ago, and I know very little about. The saw hasn't been run in at least 30 years, and is difficult to start and keep running. It has a Walbro SDC Carburetor which is marked 7-74 49, which I assume is a date and a carburetor version. From this forum I've learned that it has a fixed high speed jet like the one in the photo posted earlier in the thread. I have a few questions about this saw.

1. Is K10-SDC. the correct carb kit for this carburetor?
2. Is it ever necessary to change the fixed jet to run better on the crappy gas we get these days
3. What is the procedure for adjusting the needle valve?
4. I'm assuming I should also order a new fuel line and filter?
5. There appears to be a small filter inside of the brass fixed jet. Does this need to be replaced?

Any more pointers about this saw? According to this forum, the Pro Mac 55 seems to be a popular saw.
Thanks in advance for your advise.

1. That should be correct but compare your diaphragms to the pictures to be sure.
2. Usually no, use fresh gas, 40:1 mix with synthetic oil and they run fine if everything is in good shape
3. Walbro makes a tool for setting the metering lever height, it is brass and W shaped, Amazon has them for about $8 shipped and works on all walbro carbs
4. Yes, new fuel line, fuel filter and probably air filter
5, no leave it alone, I believe you are talking about the check valve


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[bgonzo]

1. That should be correct but compare your diaphragms to the pictures to be sure.
2. Usually no, use fresh gas, 40:1 mix with synthetic oil and they run fine if everything is in good shape
3. Walbro makes a tool for setting the metering lever height, it is brass and W shaped, Amazon has them for about $8 shipped and works on all walbro carbs
4. Yes, new fuel line, fuel filter and probably air filter
5, no leave it alone, I believe you are talking about the check valve


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I rebuilt the carb on my Pro Mac 55 and installed new fuel line, filter, and spark plug. It does seem to and start a bit better, but I think there is an ignition problem. It start and runs for a little while and then just stops. Sometimes it will cut-out and the catch again as its coasting down. I disconnected the kill switch on the handle with no change. Any thoughts on this problem? This saw has points and condenser type ignition (see attachment).

Does anyone know where I can find part numbers for ignition parts (points, condenser, coil).
Are these parts still available?

Or, does anyone know if there is an electronic ignition kit for this model?

 

[heimannm]

The coil mount for the 10 Series electronic ignition is different so your only option would be one of the points replacement chips.

https://www.ebay.com/itm/3806843323...UDQ5n7veVuRp_Z4wP_FXWN0xmwDEqyb8aAnbOEALw_wcB
Before you do that, first check the wire from the stop switch to the coil to make sure the insulation is sound and it is not grounding out at any point. Next make sure the other connections are tight; the primary lead from the coil to the terminal on the point box and the terminal on the points box where the condenser and primary lead connect to the points. Also make sure the ring terminals are not too close to the body of the saw where they could ground out. If all else fails, you may need to replace the condenser.

Mark

 

[bgonzo]

The coil mount for the 10 Series electronic ignition is different so your only option would be one of the points replacement chips.



Mark

The coil mount for the 10 Series electronic ignition is different so your only option would be one of the points replacement chips.

https://www.ebay.com/itm/3806843323...UDQ5n7veVuRp_Z4wP_FXWN0xmwDEqyb8aAnbOEALw_wcB

I noticed there is a variety of different point replacement chips available. What is different between them? Is there one which is works better, or is more ideally suited for my particular saw (Pro Mac 55)?

Is it likely that the coil itself could be the problem? Are the coils problematic?

 

[Maintenance supervisor]

Coil failure is very rare, bullet proof in my opinion. Condenser failure on the other hand is sometimes the culprit but if you haven't laid eyes on the points themselves then its any ones guess , they could be gapped incorrect or carboned up.
The little digital chips are pretty universal and I have used 2or3 in McCulloch saws and think they work quite well with no failures as of yet.
I've used Oregon and Atom2 brand. They eliminate the points and condenser but not the coil.

 

[bgonzo]

Coil failure is very rare, bullet proof in my opinion. Condenser failure on the other hand is sometimes the culprit but if you haven't laid eyes on the points themselves then its any ones guess , they could be gapped incorrect or carboned up.
The little digital chips are pretty universal and I have used 2or3 in McCulloch saws and think they work quite well with no failures as of yet.
I've used Oregon and Atom2 brand. They eliminate the points and condenser but not the coil.

Thanks for the help. I think I'll try the chip..... given that it appears to be lower cost than the condenser. I'll let you know how it turns out.

 

[heimannm]

Check out the other items first, even try replacing the spark plug as simple, low cost fixes are normally all that is needed.

Mark

 

[bgonzo]

Check out the other items first, even try replacing the spark plug as simple, low cost fixes are normally all that is needed.

Mark

I've already rebuilt the carb, changed the spark plug, disconnected to stop switch, and checked the other wiring. It still cuts-out intermittently. I might still pull off the flywheel and look at the points.

 

[Maintenance supervisor]

I do agree with Mark, the coil lead is often stepped on by placing you foot in the handle for starting and often leads to intermittent problems. So be sure to check everything out ,first.

 

[bgonzo]

I do agree with Mark, the coil lead is often stepped on by placing you foot in the handle for starting and often leads to intermittent problems. So be sure to check everything out ,first.

Good suggestion. Thanks