OS 90 4 cycle repair
03-30-2006, 02:24 PM
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RE: OS 90 4 cycle repair
Hey, Tim!!
I KNOW I'm smarter than whomever. Although smetimes, I have to admit, I act before applying my native intelligence.
If you would like, I weill allow you to use the same excuse.
Haw.
Bill.
I KNOW I'm smarter than whomever. Although smetimes, I have to admit, I act before applying my native intelligence.
If you would like, I weill allow you to use the same excuse.
Haw.
Bill.
03-30-2006, 02:45 PM
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RE: OS 90 4 cycle repair
Tim:
I would suppose it was the brown Shinola that gave you the mozt trouble. I was taught at an early age to be very careful when sniffing them, and avoid stepping in either one.
Haw again.
Bill.
I would suppose it was the brown Shinola that gave you the mozt trouble. I was taught at an early age to be very careful when sniffing them, and avoid stepping in either one.
Haw again.
Bill.
03-30-2006, 03:38 PM
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RE: OS 90 4 cycle repair
Bill I hate you, I never thought to look. I hate others pointing out the obvious that I missed.
I just opened the pack and looked at the OS 61-FS reverse cam I and couldn't find a screw thread. I haven't dismantled the motor and was hoping to get a copy of the manual before I attack it. The shaft is blank on one end and there is a 2mm threadless blind hole the other end.
My 61 is not in the least similar to the 91.
old git aka John L.
I just opened the pack and looked at the OS 61-FS reverse cam I and couldn't find a screw thread. I haven't dismantled the motor and was hoping to get a copy of the manual before I attack it. The shaft is blank on one end and there is a 2mm threadless blind hole the other end.
My 61 is not in the least similar to the 91.
old git aka John L.
03-30-2006, 04:41 PM
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RE: OS 90 4 cycle repair
ORIGINAL: grumpE
Well I think I just "did in" my FS-90. I was going to put in new bearings (finally after buying them last year). Tore it down and was haveing a tuff time with the screw that goes into the timing plate drive disk (see pic). I let it sit in penetrating oil for days. Got my T handle allen wrench and a screw driver ready and gently increased force. Then POP. The screw head broke off with the screw left in the cam. Anyone know of a parts stash out there?
Will be combing ebay and RCU for donor motors.
It is a shame as the engine was in really good shape for as old as it was. Just needed bearings and this heavy handed buffoon went and broke it.
Eric
Well I think I just "did in" my FS-90. I was going to put in new bearings (finally after buying them last year). Tore it down and was haveing a tuff time with the screw that goes into the timing plate drive disk (see pic). I let it sit in penetrating oil for days. Got my T handle allen wrench and a screw driver ready and gently increased force. Then POP. The screw head broke off with the screw left in the cam. Anyone know of a parts stash out there?
Will be combing ebay and RCU for donor motors.
It is a shame as the engine was in really good shape for as old as it was. Just needed bearings and this heavy handed buffoon went and broke it.
Eric
Eric,
I would contact Clarence Lee, he does all sorts of repares on engines. His add is in the back of AMA, no web page, you have to write or call. If any one can fix it he can.
Cheers,
Chip
03-31-2006, 01:58 AM
#32
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RE: OS 90 4 cycle repair
The reason it broke is that it's a left handed thread. Now you need a new camshaft and that little impossible to find lefthand screw.
Changing bearings in the old OS four cycles (60, 75, 80 and 90) is a lot more difficult than in the new oS engines. There are five bearings and the front cam bearing is an oddball 15x20mm stainless steel bearing.
Those parts are going to be a B---ch to find. Any parts for the OSFS90 are going to be hard to find. Lee doesn't carry parts to repair engines.
I have severel boxes of parts for old OS 4 cycles. Give me an email and I'll see what I can do for you.
Bruce
Yeah that guy, BL
Changing bearings in the old OS four cycles (60, 75, 80 and 90) is a lot more difficult than in the new oS engines. There are five bearings and the front cam bearing is an oddball 15x20mm stainless steel bearing.
Those parts are going to be a B---ch to find. Any parts for the OSFS90 are going to be hard to find. Lee doesn't carry parts to repair engines.
I have severel boxes of parts for old OS 4 cycles. Give me an email and I'll see what I can do for you.
Bruce
Yeah that guy, BL
03-31-2006, 02:27 AM
#33
RE: OS 90 4 cycle repair
ORIGINAL: William Robison
John:
I am curious to know; is the back end screw on the reverse rotation cam shaft a RIGHT hand thread? After all, reversing rotation would reverse the direction, it seems a r/h thread would be called for.
Bill.
John:
I am curious to know; is the back end screw on the reverse rotation cam shaft a RIGHT hand thread? After all, reversing rotation would reverse the direction, it seems a r/h thread would be called for.
Bill.
The OS FS61 has a front cam unlike the rear cam on the FS90.
Rod S
03-31-2006, 11:14 AM
#34
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RE: OS 90 4 cycle repair
The original FS-60 had the rear cam. The FS-61 had the front cam.
FS-60 pic in O.S. Engines timeline:
http://www.osengines.com/history/ostimeline06.html
FS-60 pic in O.S. Engines timeline:
http://www.osengines.com/history/ostimeline06.html
04-02-2006, 06:04 AM
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RE: OS 90 4 cycle repair
Timing the OS Max 61-FS.
Thanks you w8ye very much for the information about the cam timing position for the OS Max 61-FS.
I had a loook at the prop driver and front bearing housing for timing marks and was not sure of what I found. There appears to be a casting flash at the top and bottom of the bearing housing and possible plier marks on the prop driver.
I wondered therfore if I should use piston at top dead centre for the cam timing position.
old git aka John L.
04-02-2006, 07:40 PM
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RE: OS 90 4 cycle repair
Thanks very much to all for all the information, this has been a very useful thread.
I am still of the opinion that there could/should be a section to refer to for engine manuals and also hints on repair and servicing engines of varius sorts.
It also occurs to me that subjects such as covering materials and paints could also help both newbies and returnee modellers.
Perhaps the MODERATOR would like to comment.
old git aka John L.
I am still of the opinion that there could/should be a section to refer to for engine manuals and also hints on repair and servicing engines of varius sorts.
It also occurs to me that subjects such as covering materials and paints could also help both newbies and returnee modellers.
Perhaps the MODERATOR would like to comment.
old git aka John L.
