Finally started this McCulloch BP-1 project, need some parts and advice....

[Chainsaw Jim]

Us kewl kids use red armor for toothpaste.

 

[Sleeper]

Found them, got a bag of them. Measure .506" in diameter.

Used these on my 790 as I had ported it, so new plugs were required to seal off the passages.

Wonder how I did transfers on that saw? Wasn't hard. Didn't need a right angle piece to do it like the newer ones require.

Edit: If these will fit, send a pm with address and how many you need. (got about 20 or so of them)

 

[Scotty Overkill]

I sent a metering and a fuel pump diaphragm to Joe Salva some time ago hoping to get some part reproduced for the BP-1 carburetor but I haven't heard back. McCulloch used that same carburetor on the 170 Welder.

Mark

I believed I talked with Joe (Sugar Creek Saw Shop?) about that project, that was over a year ago.

For now, I've given up. I'm going to try converting a Tillotson HS to fit. I already made an adapter plate, I'm going to fabricate a carb box myself and do a cable throttle linkage. I have it all planned out in my head, just gotta do it now. As soon as I get this thing back together I'll get to work on that.

Here's the adapter plate. Still have to drill it for the carburetor mounting holes and the impulse circuit, I'll do that once I decide exactly which carburetor I'm going to try.

 

[Scotty Overkill]

Found them, got a bag of them. Measure .506" in diameter.

Used these on my 790 as I had ported it, so new plugs were required to seal off the passages.

Wonder how I did transfers on that saw? Wasn't hard. Didn't need a right angle piece to do it like the newer ones require.

Edit: If these will fit, send a pm with address and how many you need. (got about 20 or so of them)

I'll measure the transfers when I get home later this evening, I really appreciate it!

 

[Chainsaw Jim]

What size hs tillotson are you planning on using?

 

[Scotty Overkill]

What size hs tillotson are you planning on using?

Not sure yet, if I'm not mistaken the BP-1 is somewhere around 48cc? (off the top of my head), so maybe try the same that were used on the old Stihl 041's (because I have like 30 of them), do you have a suggestion?

I'm open for ideas, fellas......I'm just a redneck engineer....lol

 

[Steve]

I'm I'm not mistaken the bp-1 has a governor to prevent over speed. I'm not sure what the limits are on them but I believe they were recalled to be destroyed by McCulloch because they would over speed and explode. I'm all for this carb swap just don't want anybody to get hurt. I know Mark had that bp-399t around 22,000. That is a cool sound!

 

[Scotty Overkill]

I'm I'm not mistaken the bp-1 has a governor to prevent over speed. I'm not sure what the limits are on them but I believe they were recalled to be destroyed by McCulloch because they would over speed and explode. I'm all for this carb swap just don't want anybody to get hurt. I know Mark had that bp-399t around 22,000. That is a cool sound!

Yes I've heard that, but I've never heard what governed the RPM. Is it something in the coil?

 

[Steve]

I thought it was something in the carb that dumps fuel when it's at rpm?

 

[Chainsaw Jim]

They only discontinued because of the fear of things spinning that fast. I don't believe any ever grenaded from rpm speed.

 

[Chainsaw Jim]

Not sure yet, if I'm not mistaken the BP-1 is somewhere around 48cc? (off the top of my head), so maybe try the same that were used on the old Stihl 041's (because I have like 30 of them), do you have a suggestion?

I'm open for ideas, fellas......I'm just a redneck engineer....lol

They're 44cc, so I'd think of a carb for a hotrod saw around that size.

 

[Scotty Overkill]

I'll be careful when the time comes to open her up.......let's focus on getting to that point for now though. Lol

The BP-1 carb is a unique one for sure, I think McCulloch made a welder that used the same carburetor? I have one original carb that's stripped down and in a bag awaiting rebuild, it has a unique circuit inside it that very well may be the governor. I didn't study it enough yet to know for sure.

I wish there was some more detailed literature out there in regards to the whole BP-1 story, namely understanding EXACTLY what they were doing to be recalled and the whole project abandoned, but there just isn't a whole lot of info out there, at least that ive found yet.

 

[Scotty Overkill]

They're 44cc, so I'd think of a carb for a hotrod saw around that size.

Any suggestions for me? I'll figure out the throttle and choke as we go, I gotta take it one step at a time here....lol

 

[Chainsaw Jim]

I'll be careful when the time comes to open her up.......let's focus on getting to that point for now though. Lol

The BP-1 carb is a unique one for sure, I think McCulloch made a welder that used the same carburetor? I have one original carb that's stripped down and in a bag awaiting rebuild, it has a unique circuit inside it that very well may be the governor. I didn't study it enough yet to know for sure.

I wish there was some more detailed literature out there in regards to the whole BP-1 story, namely understanding EXACTLY what they were doing to be recalled and the whole project abandoned, but there just isn't a whole lot of info out there, at least that ive found yet.

They discontinued because they feared one would grenade in the hands of a consumer.
There's was once a time when the experts believed you'd die if you traveled faster than 70mph in a vehicle.

 

[TALLGUY]

I sent a metering and a fuel pump diaphragm to Joe Salva some time ago hoping to get some part reproduced for the BP-1 carburetor but I haven't heard back. McCulloch used that same carburetor on the 170 Welder.

Mark

Joe just got my Reed Prentice parts back to me. Only 4 years to the day. It sounds like he has been plugging away on projects.

Sent from my SM-G950U using Tapatalk

 

[Scotty Overkill]

Joe just got my Reed Prentice parts back to me. Only 4 years to the day. It sounds like he has been plugging away on projects.

Sent from my SM-G950U using Tapatalk

Yes, he talked with me about the many projects he has going on. He seems like a great guy when we talked last year, we talked on the phone for quite a while, and I'm not a telephone guy.

 

[Al Smith]

As usual the only prints I have for that saw are on micro fiche .Larry Steiner had one that didn't run and he usually come hell or high water gets them running given enough time .Dan Henry might have one also but I haven't seen either one of them on line in years I do remember the carb is a one of because of the boost cylinder that charges the power cylinder .I also think McCulloch made a lager version of that design for a snow mobile engine . McBob might have had one but he's no longer among the living .

 

[Al Smith]

BTW if memory serves that saw was goverened about 14,000 rpm which is not a big deal now but it was a big deal then .

 

[Deets066]

I ran one at Randy's 1st GTG. Way cool saw, little powerhouse for 44 cc

 

[Al Smith]

Let me do a little research on this .Got my freakin taxes done .My lady friend is island hopping on a cruise ship in the southern islands,Caribbean sea. Been there and done that under water myself . I might have some time .