All back together except for the Walbro carb (waiting for rebuild kit). I poured a little premix into the intake and it fired right up! Not much of a collector's saw but it should get some work done around my property.
McCulloch Mini and Small CC Chainsaw's
- Thread starter Overtrained
- Start date
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Rocker59
ArboristSite Member
Maybe a little late but the 35 and 38 both have the 38cc label. I did notice the cylinders had the respective cc stamped on them. I have read here before and agree from use, the 38 seems to be under powered compared to the 35.
Do the Jenn Feng McCullochs have the same ignition module issues as the Eager Beaver lineage of saws? Luckily I already have a good spare coil for the 1635.
I would say the Jenn Feng modules were actually more reliable than ones on the Italian McCulloch saws. I have not had many issues with the older McCulloch electronic ignitions (black, brown, larger white/cream colored units. I have some inside information that suggests the designs were very good, but purchasing was always pursuing cheaper suppliers and the execution of the designs were often compromised resulting in excessive failure rates. There were even reports that lots of goods that were rejected in Lake Havasu and Tucson ended up being shipped to Australia.
This type was less reliable on the smaller saws.
Mark
This type was less reliable on the smaller saws.
Mark
So I've got my 1635 back together and it runs like a dream, I just had the chance to start it, let it idle for a few minutes with a few blips of throttle. The only problem is my auto oiler doesn't seem to be pumping oil yet. I did drain the oil tank and remove the pickup line when I had it apart. Is there any sort of priming procedure I need to do? Does it need to be running at higher throttle to pump oil? It's past midnight right now so trying not to make my neighbors angry, so I never tried cutting any wood yet.
Any insight will be much appreciated!
Any insight will be much appreciated!
I'd say is a pretty good chance the oiler gear is stripped, that was pretty common on those models. You will have to pull the flywheel again, remove the oil pump and examine the plastic gear on the plunger (Item 2).
The kit is PN 301084. Maybe Max will uncover some in his inventory from Bob Johnson but I think even Bob was running low on those. You may have to find a donor saw with a working oil pump.
Mark
The kit is PN 301084. Maybe Max will uncover some in his inventory from Bob Johnson but I think even Bob was running low on those. You may have to find a donor saw with a working oil pump.
Mark
Ouch ok thanks Mark, I had a feeling you'd have some ideas.
I read sometimes they need to be primed with a lighter oil and then switched to bar oil, I'll give that a try first and then pop the flywheel off if I'm still getting nothing.
How does the plunger actually function? I can see how the worm gear (part 8) would turn it, but is it on some kind of cam lobe that creates the pumping action? I sure wish there was some way to observe it function with the saw assembled.
One last thing....there appears to be new production oil pumps that fit these saws available for about $15! They appear to fit a broad range of saws.
I read sometimes they need to be primed with a lighter oil and then switched to bar oil, I'll give that a try first and then pop the flywheel off if I'm still getting nothing.
How does the plunger actually function? I can see how the worm gear (part 8) would turn it, but is it on some kind of cam lobe that creates the pumping action? I sure wish there was some way to observe it function with the saw assembled.
One last thing....there appears to be new production oil pumps that fit these saws available for about $15! They appear to fit a broad range of saws.
Rocker59
ArboristSite Member
I was able to take one apart (remove pin at top, hope everything doesn't jack-in-the-box), clean it and replace the o-ring. Worked after that. Probably got lucky. I have also heard on this site that they don’t hold up with regular bar oil, winter weight or veg oil must be used.
Lighter weight bar oils are definitely better for the gears.
There should be a gear, Item 8 in the illustration above that drives the pump. the spring (Item 9) is only there to serves as a sort of slip clutch to drive the gear.
Mark
There should be a gear, Item 8 in the illustration above that drives the pump. the spring (Item 9) is only there to serves as a sort of slip clutch to drive the gear.
Mark
Thanks guys, I replaced the bar oil with some 0W-20 and I'm going to try running it again today as soon as I have the opportunity.
This saw has EXTREMELY low hours on it, so hopefully the gears are in good shape and I just need to get it primed.
This saw has EXTREMELY low hours on it, so hopefully the gears are in good shape and I just need to get it primed.
Update: The MS 1635 is going on the shelf indefinitely. I decided to try running it, not only is it not pumping oil but after a few minutes of running I lost spark. I'm assuming the coil is junk and quit as soon as it warmed up.
Not spending any more time on this piece of junk right now haha....I've got a 10-10 waiting to be worked on. Thanks for the help fellas, I may revisit this one in the winter.
Not spending any more time on this piece of junk right now haha....I've got a 10-10 waiting to be worked on. Thanks for the help fellas, I may revisit this one in the winter.
Welp....tore back into my MS1635 and Mark was 100% right, I can see why I'm not pumping oil:
Now to find a good oil pump.
Now to find a good oil pump.
Well, I can get a brand new pump assembly on Amazon for $17 shipped, gonna go for it.
Mark,
In your diagram, it shows 2 parts #3 and #4, is there a washer and an O ring??
I got my replacement oil pump, but the pump body is slightly different, so I had to steal the drive gear / shaft from that new pump and install it in the old pump body.
It seems like it will go together, but both pumps only have one washer in them between the spring and the brass pump body inside.
Also, are these things supposed to get re-greased on occasion?
Update: took apart another broken pump and found the washer and O-ring so I installed them in the new pump.
Bench test it seems to pump oil, but man I worry about the longevity, it seems very fragile...
Bench test it seems to pump oil, but man I worry about the longevity, it seems very fragile...
Ahh sweet victory... the MS 1635 is running and pumping oil.
All assembled... and just what I needed...ANOTHER 40cc saw haha.
All assembled... and just what I needed...ANOTHER 40cc saw haha.
It is always satisfying to solve a problem.
Mark
Mark
I get a lot of help here that makes it possible!
asc20
New Member
Hey all, hope I am not highjacking a thread by posting here, I’m new to this site. I picked up a mini Mac yesterday for $20, it has spark and compression but needs some work on the carb. I believe it’s a MM 1 but I was hoping someone here could confirm/deny and give me any pointer before I go tearing into it today.
Also, looking for at least a carb rebuild kit if not a replacement carb, if someone could point me in the right direction for reputable parts.
Thanks!
Also, looking for at least a carb rebuild kit if not a replacement carb, if someone could point me in the right direction for reputable parts.
Thanks!
Appears to be a Mini Mac 6, the most difficult model to work on since the starter does not come off the flywheel housing. You must remove the engine to access the ignition or carburetor, and pulling the engine out of the MM6 requires aligning the fins on the flywheel with the "ratchet" on the starter as you pull it out. Pull the starter rope out a foot or so as you begin the task so you can position the flywheel correctly to come out.
That saw will most likely have a Walbro MDC carburetor, kits are available from many sources but I always replace the high speed check valve on the Walbros as they seem to be highly problematic. The check valves are not included in most kits so be sure to ask, or order one along with you kit to be sure you are fully equipped.
Mark
That saw will most likely have a Walbro MDC carburetor, kits are available from many sources but I always replace the high speed check valve on the Walbros as they seem to be highly problematic. The check valves are not included in most kits so be sure to ask, or order one along with you kit to be sure you are fully equipped.
Mark
