Mcculloch sp125/101b kart saw build thread

[Scott Kelsey]

Guys, for what its worth i just stopped by an industrial bearing supplier this morning. I realize these needles can still be found to an extent, but clearly things are not getting any easier to find. The gentleman found me a supplier that has needles the same diameter as the OEM Mcculloch, even with the tapered end, but they are .120 longer. They are .30 cents a piece. He said you can grind them down and taper the end yourself, buff them and they will run fine. He had a customer do that to a planetary gear with over 400 needles, so he said. Dad was a millwright for almost 50 years and he told me there is nothing wrong with doing that as he has done it for high rpm applications at his old mill. Very interesting.

 

[Lee H]

Has anyone split a fuel tank on a 125 and resealed it. They are only held together with 3 screws and bonded.
I have a SD 166 with the same type tank. 2 piece and screwed and bonded that is in nice shape but leaking.
What did they use as a bonding adhesive. I have the tank apart and almost ready to glue and screw it back
together if i can find out what to use for an adhesive.

 

[jacob j.]

Lee -

@Stevetheboatguy just posted about some metal adhesive that looks promising - https://opeforum.com/threads/jb-weld.26212/#post-1352760

I'm not sure on the Dolmars but an old-time McCulloch distributor told me they used aircraft panel adhesive on the 125 tanks. It seems to have a
consistency similar to JB Weld as a cured product.

 

[Maintenance Chief]

Has anyone split a fuel tank on a 125 and resealed it. They are only held together with 3 screws and bonded.
I have a SD 166 with the same type tank. 2 piece and screwed and bonded that is in nice shape but leaking.
What did they use as a bonding adhesive. I have the tank apart and almost ready to glue and screw it back
together if i can find out what to use for an adhesive.

I had a SP80 getting leaks on the seam, I used slow cure JB weld and Red Cote on the inside of the tank. Its been several months and temperatures with no leaks.

 

[Al Smith]

You have "seal all " for one of many .I'm not certain if Loctite 5900 would work on gasoline but it does for oil and in fact has all but replaced gaskets on auto engines from Ford to Rolls Royce .What might work is Permatex aviation which is listed as gasoline resistant and has been around forever .I can tell on the few occasions I've used it on it does work .Sloppy chit but it works . I had a leaky fuel fill line on my Ranger and did a half-fast fix using buna N sheet stock slobbered up with Permatex aviation and four hose clamps because it was colder than well diggers behind out at the time .It held until spring time when I replaced the hose .

 

[Lee H]

I had a SP80 getting leaks on the seam, I used slow cure JB weld and Red Cote on the inside of the tank. Its been several months and temperatures with no leaks.

I have the tank already split and looking to use a correct adhesive like the factory did
to bond the 2 halves back together.

 

[Stevetheboatguy]

Lee -

@Stevetheboatguy just posted about some metal adhesive that looks promising - https://opeforum.com/threads/jb-weld.26212/#post-1352760

I'm not sure on the Dolmars but an old-time McCulloch distributor told me they used aircraft panel adhesive on the 125 tanks. It seems to have a
consistency similar to JB Weld as a cured product.

Be careful if you use the fusor. I have used it to repair many leaking gas tanks and a couple of diesel tanks. Not one has leaked or had any ill effects. But if it is something that might ever have to come back apart......... Do not use it. You will have to cut it apart. It withstands high temps pretty well. I thought I could use a propane torch to soften it up and break the bond on something that I needed back apart. It didn't work. I spent a hour with a hacksaw blade cutting the seam. Learn from my mistake


Steven

 

[Lee H]

Be careful if you use the fusor. I have used it to repair many leaking gas tanks and a couple of diesel tanks. Not one has leaked or had any ill effects. But if it is something that might ever have to come back apart......... Do not use it. You will have to cut it apart. It withstands high temps pretty well. I thought I could use a propane torch to soften it up and break the bond on something that I needed back apart. It didn't work. I spent a hour with a hacksaw blade cutting the seam. Learn from my mistake


Steven

Thanks for your input & experience Steve, I just want this tank and any others in the future
to be glued or bonded like factory and never have to separate them again.

 

[heimannm]

I have had a couple of CP125 tanks that leaked, sealed them with Red Kote and as long as you let it cure completely before adding fuel it has been a 100% positive solution. I have done many of the 70 and 82 cc saw fuel tanks as well since the CP and SP models are all sealed and all with very positive results.

The only possible fly in the ointment is if you get it on too thick and do not let it cure completely. In the winter months a week above the wood stove seems to do the trick. In the summer I put them in the attic of the garage and a week of 120 -140 degrees up there also works.

I do remember Ron Woods experience trying to take a tank apart, if I recall correctly he had to resort to a hacksaw.

I did manage to get the tank apart on a SP70 a few years ago, ended up breaking all but one screw so I had to drill them out and install inserts. I know the final leak on that one did succumb to a bit of Threebond 1184 externally applied and I learned very quickly that my favorite silicone sealers were not up to the task of fuel tank sealer. I suspect the whole tank was sealed with Threebond as well but I really don't remember.

I don't really know what McCulloch used to put the tanks together at the factory but considering the number of units produced and the relatively small number that every leaked, it must have been good stuff.

Mark

 

[qurotro]

But how does a 125 fuel tank come apart? I didnt see screws around it.

 

[Bigmac]

But how does a 125 fuel tank come apart? I didnt see screws around it.

The is one screw in the air box under the fuel line, and two under the front near the wrap mounts. Three total

 

[Scott Kelsey]

I took this tank apart yesterday. Heat gun on the screws and they backed out. I put the tank in the oven at 350° for 8-10 minutes, pulled it out with oven mits, went to the shop, had the top part of the tank in my right hand with thumb inside of fuel cap hole. I than took a small mallet and gently hit where the handle bar clamps mount, and I started to see the front of the tank separate at the seam. I than used both hands and pulled it apart. No worries as although the oven gets to 350° infrared thermometer said the tank did not get near as hot. No warping, etc. I let it naturally cool and all is well.

 

[Lee H]

I took this tank apart yesterday. Heat gun on the screws and they backed out. I put the tank in the oven at 350° for 8-10 minutes, pulled it out with oven mits, went to the shop, had the top part of the tank in my right hand with thumb inside of fuel cap hole. I than took a small mallet and gently hit where the handle bar clamps mount, and I started to see the front of the tank separate at the seam. I than used both hands and pulled it apart. No worries as although the oven gets to 350° infrared thermometer said the tank did not get near as hot. No warping, etc. I let it naturally cool and all is well.

Scott what are you planning to use for a bonding adhesive.

 

[Scott Kelsey]

Lee, I have been looking at several products, but at the moment I want to do more research on PPG's products such as this. Ultimately, I want to get in contact with a PPG representative and ask their thoughts after showing them pictures of a 125 fuel tank. They have more than one variation of fuel tank sealant. This is just one of them.

 

[Lee H]

I have been looking at the Lord Fusor products that @ Stevetheboatguy used but unsure
of being gas resistance or not.

 

[Scott Kelsey]

Was looking at my two project saws this weekend and the 101 saw I intend to build the fuel tank did not come with a fuel cap. Do you guys know of a replacement fuel cap that would work? I have been searching for and also watching Ebay for a nos fuel cap with no luck. I would assume the fuel cap needs to have the hole for a duck bill valve to allow the tank to breathe, but I see SP125's with caps that do not look like they have vented fuel caps. Anyone have some insight?

 

[jacob j.]

McCulloch made several different styles of the same-sized fuel cap to fit different applications, like the 170 welder, Demolition/cut-off saws, water pumps, etc.

Some of the different styles had different vents or no vents at all. You'll wanted a vented cap on the 125s because there's no vents in the fuel tank.

I should have a spare cap for you.

 

[Bigmac]

If you’re fabbing a tank, there are several options, and it also depends on what you’re gonna use the saw for. A race saw on my drag Quad, I just run a hose as a vent, They make these little one-way valve nipples for dirt bikes as well

 

[heimannm]

Fuel caps for the old McCullochs are plentiful, if JJ can't help you I can find a spare or two.

Mark

 

[Bigmac]

Sorry I misread the first part, I saw the “I intend to build the fuel tank” part and went off in a tangent! A 101 saw with and sdc20 will be fine with a stock fuel cap, I have had to pull the duckbill out to get the cap to breath, on the wb saws