Roper 3.7 tear down and rebuild

[Opihi59]

Messed with the Roper some more today after I put away the two 55's. I can get it to run, but it isn't easy. As it starts, it will suck the choke wide open, and kill itself unless you block the choke with your finger and feather the throttle. It skips/misses at open throttle. I finally managed to get it to sit and idle which I let it do for about 20 mins til it ran outta gas. I had screwed in the low speed screw, then backed it out 1.5 turns first. It really doesn't seem to be running well at all. I am supposing it could be the new rings seating, so hopefully letting it idle thru a 1/4 tank may help them seat better. I cannot explain the skip/miss at more open throttle but not sure it could pull a chain thru many twigs right now. Of course, it ran pretty doggone good but with low compression before the rebuild. It has all new fuel lines and it ran on these before the new rings. I'm curious if it needs some better exhaust flow since it has higher compression, I didn't have the exhaust cover screws on tight, and one fell out, the cover would blow out when I brapped the throttle meaning to me, it needs better exhaust flow? Any idea why it would suck the choke open by itself? For now, leaving it on the bench til I come up with a fix for my other project saws.

 

[Mastermind]

Could it be an electrical thingy??? Just thinking out loud here...

 

[Roanoker494]

Messed with the Roper some more today after I put away the two 55's. I can get it to run, but it isn't easy. As it starts, it will suck the choke wide open, and kill itself unless you block the choke with your finger and feather the throttle. It skips/misses at open throttle. I finally managed to get it to sit and idle which I let it do for about 20 mins til it ran outta gas. I had screwed in the low speed screw, then backed it out 1.5 turns first. It really doesn't seem to be running well at all. I am supposing it could be the new rings seating, so hopefully letting it idle thru a 1/4 tank may help them seat better. I cannot explain the skip/miss at more open throttle but not sure it could pull a chain thru many twigs right now. Of course, it ran pretty doggone good but with low compression before the rebuild. It has all new fuel lines and it ran on these before the new rings. I'm curious if it needs some better exhaust flow since it has higher compression, I didn't have the exhaust cover screws on tight, and one fell out, the cover would blow out when I brapped the throttle meaning to me, it needs better exhaust flow? Any idea why it would suck the choke open by itself? For now, leaving it on the bench til I come up with a fix for my other project saws.

Don't go jumping the gun and buying a replacement carb because the "package" I sent contains a full adjustable Tilly HS, carb spacer, rubber grommet for the adjuster screws and a fresh oem carb kit. All you will need is a couple of carb base gaskets, which can be easily made from sheet material.

 

[67L36Driver]

Messed with the Roper some more today after I put away the two 55's. I can get it to run, but it isn't easy. As it starts, it will suck the choke wide open, and kill itself unless you block the choke with your finger and feather the throttle. It skips/misses at open throttle.

Somewhere along the line when the carb. was disassembled, the ball detent and spring has been lost from the choke shaft. The sring and then a tiny steel ball fits in a hole 90 deg. to the choke shaft. The choke shaft has a dimple so the detent will hold it open. The detent also adds enuff friction so it won't suck open.

Most all Tilleys and Walbros have them.

I had to use a ball of bead (key) chain and a section of ball point pen spring on the Carter ND in one of my Remingtons.

 

[Opihi59]

Hard to jump the gun on this cinder pile in the middle of the Pacific--I will be watching for the package. Out here I have to be patient. I can't wait now for the mail to come......course, I gotta wait for the weekend to play with the saws again. I'm excited, hope you'll be able to teach me what to do with the stuff when it gets here.

I never had an issue with the choke sucking itself open before, hard to say why that started. Does it have anything to do perhaps with restored compression? Makes it suck harder too?

Mastermind--I suppose it could be an issue with an electrical thingey as well, but not quite sure how to check. It does make spark, the air gap is set fine on the flywheel, etc. When I get it to run, it burbles along nicely on idle, but has the miss/skip on opening the throttle.

 

[Opihi59]

Drive sprocket

Since I had acquired a pair of Husky 55's this weekend and tore into them, I had a few thoughts. The 55's I got have 3/8 pitch drives, and this Roper is .325 pitch. I was looking at the sprockets and found that they are essentially interchangeable with some differences. Key thing is that they both have matching 7 splines, and will fit perfectly onto the clutch hub. Side by side comparisons. Husqvarna on left, Roper on Right--Reverse side view.

Roper:

Husqvarna:

Flip side, or Obverse as the numismatic enthusiasts amongst the AS fold would say.

The key difference to note is the difference in thickness, the Roper has a flange/boss on each side of the drive sprocket. I feel I could match this with spacers, and then run the 3/8 sprocket on the Roper allowing me to swap over to an easier to find Bar/chain combo on the Roper so I may not have to modify a D176 (also hard to find in .325) or go to a K041 .325 bar which can be made to work as well.

I somehow feel this is an independant discovery of some sort, but folks likely already know this out there. Does anyone have any thoughts about doing this as an option? I just happen to have a spare 55 drive sprocket in 3/8 pitch since one of my 55's is a parts saw.

 

[67L36Driver]

Rim sprockets are supposed to float on the spline hub so the chain can align itself with the bar. The extra thickness on the one will have a little effect, but not much. They are escentially interchangeable.

Change the Roper to 3/8" x 7 or whatever to suit the bar nose.

Sudden thought: The extra thickness on the .325 x 7 is so the chain will align with the (obsolete) Power Sharp contraption.

 

[Opihi59]

Wear?

So just looking at the photos again, those divots in the rim of my Roper sprocket--are those from wear? Or is that the way it was made?
On the Husqvarna sprocket, I notice some "bright" spots that to me appear that they could be an indication of early wear, and with more time/use, they will deepen.

Anybody have thoughts on that? Is my Roper sprocket totally shot?

 

[Chris J.]

So just looking at the photos again, those divots in the rim of my Roper sprocket--are those from wear? Or is that the way it was made?
On the Husqvarna sprocket, I notice some "bright" spots that to me appear that they could be an indication of early wear, and with more time/use, they will deepen.

Anybody have thoughts on that? Is my Roper sprocket totally shot?

Yes, the Roper sprocket is shot. Don't try use it, you'll mess up the drivers on your chain (a lesson I learned the hard way with a brand new chain).

 

[67L36Driver]

Yes, the Roper sprocket is shot. Don't try use it, you'll mess up the drivers on your chain (a lesson I learned the hard way with a brand new chain).

Yup, that puppy is done.

 

[Opihi59]

Bleah

Yup, that puppy is done.

Well doo doo.....................shux, where can I find a replacement? Anyone know of any substitutions or sources? Since I found out the Husqvarna fits and comes in .325 as well as 3/8, I may look for one of those, so I can still run my brand new chains I already bought. I'll poke around and see what I come up with and post up results when I come across something that works.:msp_mad:

 

[Opihi59]

Just went to look for a PN on Searsparts.whatever and they list it as available, so I bought two. Why not, I have 2 Ropers. They wouldn't allow "standard shipping" since I live on a rock and they had some extreme super expensive mode where a limo brings it directly to my house where a tuxedo wearing attendant hands it to me, apparently based on how much they wanted me to pay. It therefore gets to go to my Sister's house in rural KY and she can put it in a small envelope and shuttle it to me for about $2. We've had to do that a lot with tons of stuff, it is a pain for her but it ends up way way cheaper from some places that won't ship without some predatory pricing penalty. "Paradise Tax." Bastigiz!! At any rate, we'll see what the new ones look like. Good thing that I am not in a hurry and this is a labor of love.

 

[Opihi59]

Don't go jumping the gun and buying a replacement carb because the "package" I sent contains a full adjustable Tilly HS, carb spacer, rubber grommet for the adjuster screws and a fresh oem carb kit. All you will need is a couple of carb base gaskets, which can be easily made from sheet material.

Package got here with a very nice little HS 79A Tilly carb and gasket/diaphragm set. I tried to send PM, but your box is choked and I didn't want to not let you know it had got here intact and fine for its Hawaiian vacation. I'll put it on this saw when I get a moment depending on how late I get home from work this week and see how it goes. Even the Dragon Lady said "what a cute little carb..." If she had paid any attn to my Walbros and Zamas, she'd likely recognize its a Mongo big unit.

Thanks!!! :msp_thumbup:

 

[67L36Driver]

Speaking of shipping.

The coffee made the trip. Thanks bud.

Still tinkering with the dosage required on my little 4 cup maker.

 

[Opihi59]

The coffee made the trip. Thanks bud.

Still tinkering with the dosage required on my little 4 cup maker.

Err on the strong side, dilute with hot water to your liking. It's certainly not Kopi Luwak, but Kona Coffee is reasonably decent stuff.

Roper action is on the side at the moment while I work on the 2.3 oiler issue. I was wanting to use that saw this weekend but it will all have to wait. Whatever parts arrive in the mailbox first dictate which needy saw gets the attention. My wife asks me how I keep it all straight, but somehow, it all makes sense.

 

[67L36Driver]

Err on the strong side, dilute with hot water to your liking. It's certainly not Kopi Luwak, but Kona Coffee is reasonably decent stuff.

Roper action is on the side at the moment while I work on the 2.3 oiler issue. I was wanting to use that saw this weekend but it will all have to wait. Whatever parts arrive in the mailbox first dictate which needy saw gets the attention. My wife asks me how I keep it all straight, but somehow, it all makes sense.

Normally we use one generous tablespoon of Folgers Blak Silk in my 'maker. We are up to two heaping tablespoons of Kona. Tastes good.

Must not take much to wake up sandwich islanders.

I tried to have only one saw major project going at a time.

That has gone out the window as I have two XL-113 types getting major overhaul, a C5 getting fuel tank repair and more, an XL-800 for major rebuild (lots of expensive parts needed), a Poulan 655 (Pioneer P62) needing fuel tank repair and maybe rings and lately a Wards Powr-Kraft (David Bradley) undergoing evaluation.

I need to discriminate more carefully which orphans to adopt.

 

[Opihi59]

Must not take much to wake up sandwich islanders.

For whatever reason, caffeine has no effect on me per se as far as sleep/wake issues. I have determined though that it serves as a facultative neurotransmitter--without it none of my standard cerebral neurotransmitters can function. I suppose if I had a caffeine transdermal patch I wouldn't spend so much time going whiz.

Hoping this weekend or so I can post up more progress on this build, but I am sidelined by a Jeep issue now.

 

[Opihi59]

New carb action

I put the rebuild kit in the new HS 79A carb and installed it, could only get the saw to fire very briefly then immed die. For the 0.376 seconds it fired, it sounded very robust. But it died. I took carb apart, checked all passages again, checked the assembly of diaphragms and gaskets, checked the feed valve, all looked fine. It is just not feeding fuel. I can get it to fire if I pour gas down the carb, then crank, but no change. I checked the fuel lines by blowing air both ways, then I disassembled the entire saw again, pulled piston, cylinder, took apart bottom end, blew out anything that could be in there, rings look fine, etc, checked all pulse lines, gaskets, reed valves, everything. Then put it all back together after checking carb gaskets and diaphragms again. Still wouldn't run. Of course, I am certain I have the rebuild kit in correctly (but you've all heard that before......but I am certain it is right) I had dialed out the low/high needles to 1.5 then 2.0 turns after gentle seating. Of course, blew all this out with carb cleaner, etc. No compressed air........

So I put it down for the weekend. Not sure what else to do, or what to check. I am certain it is a carburetion problem, and this is the second carb now. It's more than just a little bit annoying. On another note, I have time to drink beer now.

Happy to receive suggestions. I'm not going to drop this, this is THE saw I want to run if any of them are gonna run.

 

[67L36Driver]

I put the rebuild kit in the new HS 79A carb and installed it, could only get the saw to fire very briefly then immed die. For the 0.376 seconds it fired, it sounded very robust. But it died. I took carb apart, checked all passages again, checked the assembly of diaphragms and gaskets, checked the feed valve, all looked fine. It is just not feeding fuel. I can get it to fire if I pour gas down the carb, then crank, but no change. I checked the fuel lines by blowing air both ways, then I disassembled the entire saw again, pulled piston, cylinder, took apart bottom end, blew out anything that could be in there, rings look fine, etc, checked all pulse lines, gaskets, reed valves, everything. Then put it all back together after checking carb gaskets and diaphragms again. Still wouldn't run. Of course, I am certain I have the rebuild kit in correctly (but you've all heard that before......but I am certain it is right) I had dialed out the low/high needles to 1.5 then 2.0 turns after gentle seating. Of course, blew all this out with carb cleaner, etc. No compressed air........

So I put it down for the weekend. Not sure what else to do, or what to check. I am certain it is a carburetion problem, and this is the second carb now. It's more than just a little bit annoying. On another note, I have time to drink beer now.

Happy to receive suggestions. I'm not going to drop this, this is THE saw I want to run if any of them are gonna run.

Check carefully the impulse passage from the crankcase to the carb.. Flange gaskets that come with generic repair kits are sometimes off on the hole for the passage.

I had something similar with my first Rem. 75A. The impulse hole was off by an hour (clockwise) or two.

Using the semi-transparent green fuel line? Crappy line but great to monitor fuel flow.

 

[Opihi59]

Check carefully the impulse passage from the crankcase to the carb.. Flange gaskets that come with generic repair kits are sometimes off on the hole for the passage.

I had something similar with my first Rem. 75A. The impulse hole was off by an hour (clockwise) or two.

Using the semi-transparent green fuel line? Crappy line but great to monitor fuel flow.

I suppose if I can figure out which hole is what, I'll try that. Will take it apart again....................but not this weekend. I'm DUN. I went and cranked up 2 other saws I had put together just to hear them run and let the neighbors know I wasn't sick or something. They're having a Halloween party I intend to crash later for free beer and whatever food they have laying around. Maybe take a chainsaw with me and some sorta Freddy Kruger facemask.

Tygon line--is that bad stuff? I thought it was the stuff to use.