Roper 3.7 tear down and rebuild

[RobertJ]

Wow! I only have 5. I sure wish someone would turn up a bunch of NOS Air cleaner plastics. I know, pipe dream.

 

[RobertJ]

This thread is dead, it appears. Sure wish someone would re-create the plastic Squarish air cleaner cover. Better plastic, if possible

 

[s sidewall]

Mine is the white molded brittle plastic. Super glue can only hold so much together. And it would be a puzzle trying to make it complete. It still does what it's supposed to do.

Steve Sidwell

 

[RobertJ]

Mine is the white molded brittle plastic. Super glue can only hold so much together. And it would be a puzzle trying to make it complete. It still does what it's supposed to do.

Steve Sidwell

The black plastic is very brittle, like all old plastic gets. Designed-in obsolescence ? I pulled the antenna on my Zenith Trans-Oceanic 3000-1 over a week ago, and the red plastic knob just crumbled in my fingers. Can't find one, yet. I can make one out of epoxy, but very time consuming. Sure not going to try that with air cleaner cover. LOL

 

[Huskybill]

I sanded and used epoxy on one 2100 husky air cleaner cover. Sanded it down again and maybe some filler next with paint.

Check eBay often?

 

[RobertJ]

Check eBay often?

Yes, often. I did score one about a year ago. I only need one more.

 

[s sidewall]

Mines a shelf queen that gets started once in a while when I want my ears to bleed. Had to split the case on it, was leaking fuel near the rear handle. Only reason the cover got broke is from the compression snatching the starter handle out of my hand twice. Lesson learned on using the decompression setting.

Steve Sidwell

 

[RobertJ]

I haven 't even touched my 3.7's since about Sept. I have one more in the queue to do. Mostly carb, and split the cases for that dreaded leak problem. Been busy with restoring old radios, and related gear. Now, I'm about ready for riding the bike. If we don't end up under marshal law. TIC.

 

[RobertJ]

Wow, this thread sure died, kinda like Woolworths or K-mart. LOL

 

[Spudhut]

This classic thread needs to be made a sticky!!

Wanted to add a note that the 2 screw Tillotson HS-79A carb did NOT use a main nozzle, so you’ll NOT have a check valve!

I rebuilt & ran my standard pressure tests on one yesterday, and thought it was failing the check valve test. It was not!

Called VE Petersens to confirm. They said there’s only a handful of HS series carbs that had the main feed drilled directly into the venturi.

My Saw: Craftsman 3.7A 917.351771

Driving this thread back up. Is it not a good idea to put the 2 screw HS-79A on? Is it better to run the old single screw adjuster? I would like to put the Low/High adjustments if possible.

What about the 2 screw Tilly HS161A?

What Muffler mods have people done on these?

 

[hotshot]

The Tillotson HS-79A (adjustable 2 screw carb) can be a good upgrade from the HS-143 fixed high carb. Never have messed with modding the mufflers on those, but a richer high speed adjustment is usually required when you do.

Believe that the HS-161A is the same sized later model carb, but used a smaller hose barb fitting. If you call the distributer, VE Petersens in Ohio, they can pull up the two carbs for comparison. I do remember that both the 79 & 161 carbs have an enrichment type governor valve & the odd “air leak” bleed hole drilled right in front of the throttle shaft linkage.

 

[slimbo3006]

for those interested....
https://www.ebay.com/itm/AIR-FILTER...278935?hash=item52496e3a57:g:QsgAAOSw4cdgTX09

 

[Spudhut]

Thanks guys for the reply. Glad to see life coming back on this one.

I picked up this saw from flea bay to run it with my Poulan made Craftsman 3.7. I ran the 3.7 on a few trees but its down at the moment cause the plate that holds the fuel stop in the Walbro broke at the small forks flooding it beyond runability . Now I'm in a search to find another stock carb (HDB) or fuel stop plate insert. Regardless, I got the Roper to run tonight and boy is it crazy tough to turn over (insane compression). I pulled the spark plug and it turns over nicely, but with plug in place and holding it in your hands and pull starting it like a low cc saw is nearly impossible unless you want to smack yourself in the face with it. I splashed a little fuel in it and nicely enough, it fired off almost immediately and idled. I will rebuild the carb as I saw some fuel leak by and try the HS-79A for grins. I popped open the muffler and to be honest, why Mod it when there is nothing in it but a screen. I should have checked before asking. With the cover off, its super loud.

A few other questions:

There is a +/- knob to the left, is this to control the amount of bar and chain oil flow? I have read these could have decompression valves, but I believe in this model I have, its all in the trigger and top switch.

This saw has a 5/16 chain on it with an 18" bar. Id like to run a 3/8 chain (skip tooth or ripper) and bar set, 20"-24" or maybe 28" (unless you think its unadvisable) to run on my Granberg 24" chainsaw mill. I have a Homelite Super XL that has a manual oiler, but to have a spare with high CC's to mount to it would be nice. What you guys think? What clutch and sprocket assembly would you recommend?

I love old saws. I build hot rods for 20 yrs and have moved on. I have always loved old tools. Never have I showcased them, I like to refurb them and run them like I stole them like they were intended. Im also looking at a few old Macs (10-10a, 10-10) and Homelite Super 2's. I do have a new 42cc 16" Craftsman and 46cc 20" Craftsman that I slightly modded for quick grab and go use. I keep them all tuned and sharpened ready to work.

 

[s sidewall]

Which Model of sears roper do you have? I've got the sportster model 3.7. My decomp is part of the kill switch, you pull it back to set decomp. The + and - is oil flow, the oil pump knob is a pressure type system on mine. Just push and let it flow.

Steve from my moto g(7) play using Tapatalk

 

[Spudhut]

Mine is Craftsman 3.7A (917.351771). Grey and White Model.

 

[hotshot]

I ran the 3.7 on a few trees but its down at the moment cause the plate that holds the fuel stop in the Walbro broke at the small forks flooding it beyond runability . Now I'm in a search to find another stock carb (HDB) or fuel stop plate insert.

Would be best to post the Poulan parts questions in the Nik’s Poulan “Chainsaw Stickies” thread or the Tradin’ Post, Parts Wanted stickie thread in the Equipment Forum.

Those HDB circuit plates, Walbro #157-608, have been obsolete/NLA for quite some time now, probably due to that staked-in lever pin design.

Even used OEM Walbro carbs, HDB-8 & -18 or -19, are getting hard to locate but do occasionally come up for sale on fleabay.

Another option is to try to find a used $10 Echo or Mac HDB carb for parts, then plug & re-drill the orifice to match the diameter of your old one.

 

[Spudhut]

Thanks Hotshot, I mingled over there and posted.

Back on subject - This Roper saw has a 5/16 chain on it with an 18" bar. Id like to run a 3/8 chain (skip tooth or ripper) and bar set, 20"-24" or maybe 28" (unless you think its unadvisable) to run on my Granberg 24" chainsaw mill. I have a Homelite Super XL that has a manual oiler, but to have a spare with high CC's to mount to it would be nice. What you guys think?

What clutch and sprocket assembly would you recommend?

 

[s sidewall]

Here's mine. These saws are really loud and have Dr. bills compression. Takes a good shoulder and arm to start mine unless you use the decom on it. Even with it on it still has descent compression.

Steve from my moto g(7) play using Tapatalk

 

[Goinwheelin]

Haven’t read the entire thread yet but I picked this up at a swap meet yesterday. Compression felt good and it had the roller nose bar so I figured why not.

Piston looked good and it ran on prime. Mag rot on the handle seems weird because that’s the only spot it really has it. She’s a stout pull for sure.

 

[Spudhut]

Great find @Goinwheelin