Mac 2-10 bullfrog carb part#
- Thread starter MapleMan357
- Start date
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Download the ipl off this page and figure out which carb you have. This carb went obsolete a long time ago and most people, myself included, just replace it with SDCs. Parts will be a problem.
https://www.leonschainsawpartsandrepair.com/mcculloch-literature.html#/
There are aftermarket diaphragms out there but your challenge will be the 'hard' bits.
https://www.leonschainsawpartsandrepair.com/mcculloch-literature.html#/
There are aftermarket diaphragms out there but your challenge will be the 'hard' bits.
If you determine what parts you need, I have quite a variety of bit for the bullfrog carburetors...but you have to come up with part numbers.
Mark
Mark
Rocker59
ArboristSite Member
Type 5, Double Needle, No Governor. PN: 66511. Diaphragm/pump assy. PN: 65608.
I have these marked 65608 but they don't seem to agree with the carburetor body shown above.
Mapleman - can you post a photo of the diaphragm that was in that carburetor.
Mark
Mapleman - can you post a photo of the diaphragm that was in that carburetor.
Mark
Rocker - can you tell me if these part numbers are correct?
This one without a part number?
Mark
This one without a part number?
Mark
I've installed Tillotson carbs in place of the bullfrog type with good results due to what you are getting into.
Rocker59
ArboristSite Member
As far as part numbers go, I only have a few diaphragms in open packaging, probably not much help currently. Maybe soon though. After seeing your picture of 85608, I started digging and found that there are two single and two double needle carb bodies. The first has the thin slit outlet, the second has much wider outlet. The jet discharge is also very different. The 85608 is for the larger outlet. MapleMan has the smaller. The 10 series shop manual I have mixes pictures and does not distinguish. I will collect data and compile it over the next few days. I feel a monograph coming on….
Rocker59
ArboristSite Member
So, what I am seeing is that there are only two main types of diaphragm assys., the Small Discharge and Large discharge. I believe the three primer suction configurations could be an evolution, two hole (63013/65410), three hole (65598), hole-slot (673567) for the small discharge. For the large discharge, I can find a two hole (63308) and a hole-slot (65608). There are some NOS Diaphragm assys. That seem to have gaskets that are either mis-cut or have shrunk. For the replacement gaskets I cut, I opted for the hole-slot combo with no issues.
I believe that the three small discharge diaphragms are interchangeable and the two large discharge are interchangeable. The Large discharge has an extra hole for the path to the discharge, making the Small and Large discharge diaphragms incompatible.
From the pictures MapleMan posted, it appears that he has the 63013/65410 diaphragm assy. (minus the gasket).
Stay tuned for installment two of Bullfrog Blues....
I believe that the three small discharge diaphragms are interchangeable and the two large discharge are interchangeable. The Large discharge has an extra hole for the path to the discharge, making the Small and Large discharge diaphragms incompatible.
From the pictures MapleMan posted, it appears that he has the 63013/65410 diaphragm assy. (minus the gasket).
Stay tuned for installment two of Bullfrog Blues....
Thanks Rocker. On the plus side, I don't have any current projects with the bullfrog carburetors...on the other hand I have a box of bullfrog carcasses and several saws where they could be used. I'm sure the day will come when I have to get back into the bullfrog carburetors.
Mark
Mark
Rocker59
ArboristSite Member
Hopefully this will help explain the differences between the different types of Bullfrogs If anyone has any suggestions, please let me know.
Single vs. Double Needle
The bodies look similar depending on the throat. Both small throat (above) have similar bodies. Single Needle only has one needle (obviously) but has two range limiter screws (high Low) for that needle. The Primer is a closed back with a long shaft. The double Needle only has one limit screw for the first needle and an additional needle towards the middle of the body. The primer is an open back with a short shaft. The undersides look the same depending on Small or Large Throat.
Internally, the only differences are the flow port to the Throat Discharge. Small throat above.
Above is a series of pictures explaining the fuel flow through the carbs. Single needle used as example. Mirroring made sense in my brain.
Single vs. Double Needle
The bodies look similar depending on the throat. Both small throat (above) have similar bodies. Single Needle only has one needle (obviously) but has two range limiter screws (high Low) for that needle. The Primer is a closed back with a long shaft. The double Needle only has one limit screw for the first needle and an additional needle towards the middle of the body. The primer is an open back with a short shaft. The undersides look the same depending on Small or Large Throat.
Internally, the only differences are the flow port to the Throat Discharge. Small throat above.
Above is a series of pictures explaining the fuel flow through the carbs. Single needle used as example. Mirroring made sense in my brain.
Rocker59
ArboristSite Member
Small Vs Large Throat
Difference is obvious when looking at the bottom of the carb. The Large throat has 4 body screws whereas the small has 5.
Rear view
Internal differences. The large has an additional passage for the fuel flow to the discharge that passed through the Diaphragm Assy. Note the primer discharges for Single, Double, Small, and Large are all the same even though the Single and double have different primer configurations.
I will check this weekend to see if I have a Large Throat Single Needle ( I do not think I do). If anyone does, please let me know if it is the same internally as the Double Needle above.
Difference is obvious when looking at the bottom of the carb. The Large throat has 4 body screws whereas the small has 5.
Rear view
Internal differences. The large has an additional passage for the fuel flow to the discharge that passed through the Diaphragm Assy. Note the primer discharges for Single, Double, Small, and Large are all the same even though the Single and double have different primer configurations.
I will check this weekend to see if I have a Large Throat Single Needle ( I do not think I do). If anyone does, please let me know if it is the same internally as the Double Needle above.
Thanks Rocker for all the work put into these posts.
I will try to find some time in the coming days to study them more carefully and have a look through my box of MAC10 carburetors to see if I can add anything to the discussion.
Mark
I will try to find some time in the coming days to study them more carefully and have a look through my box of MAC10 carburetors to see if I can add anything to the discussion.
Mark
