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Discussion Starter #1
in 1973 OMC built some sled with rotary engines i found one and have no clue as to what I'm doing with it my previous expirianc has been with sleds with pistons this one is a lot diffrant. i got it to run but cant get it to rev over 2800 rpm while in nutral and stuggle to make 2100 in gear. it has a top speed as of now of 20 mph down hill with a tail wind and sprays gas out the carb on W.O.T. i changed out the surface gap plug for a standard plug that made little or no differance. i tore the carb apart and its clean nothing clogged no old gunk there is only one adjustment on the carb and its center rear on top this makes vary little change even removed or tightend down compleatly any help will be apreaciated, thanks JOSH:cussing:
 

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Rotary Bogg!

There were a few different companies back in those days that had Rotarys in them. They did not have a long engine life even back then. The very first thing I would check is compression. Get the specs and check it out first thing. The rotors in these engines have what they call wipers, or vanes. Which are what contacts the cylinders. and they wear out. Or if it has been sitting around they maybe stuck and not working correctlly.

PS. not talking down on what you have for a sled but They are a real high maintance vehical. My Dad owned one back then and were a pain even when new!!
 

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think i found the problem, the magnetic surfaces inside the fly wheel were all covered with what looked like tar and dirt I'm guessing oil and a lot of dust. also the spark plug hole was on its way to striped and after cleaning the fly wheel the spark plug blew out it started for a second and sounded good until the plug was massacred by the rotor and then blown out by compression who knew you had to have a surface gap plug?
:Guillotine_anim:
 

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well the plug is fixed and the magnets are clean the fuel is fresh and still only 20 MPH. did these sleds have a spark advance system or not? it acts like its out of time at high end almost like if your vacume advance on an old car or truck wasn't working i don't find any advance mechanism as far as mechanical like some older skidoos this is closer to a boat as far as electronics except my 35 hp evinrude outboard has an advance connected directly to the throtal. PLEASE ANY ADVICE WOULD BE HELPFULL!:cussing:
 

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well i dont know too much about these motors but i had a similar issue with one of my olympics. it wouldnt do sh*t for speed. my carb looked clean as well but i replaced the diaphragms in the carb with all new screens and that fixed the problem. its worth a shot
 

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rc trailblazer issues

well the plug is fixed and the magnets are clean the fuel is fresh and still only 20 MPH. did these sleds have a spark advance system or not? it acts like its out of time at high end almost like if your vacume advance on an old car or truck wasn't working i don't find any advance mechanism as far as mechanical like some older skidoos this is closer to a boat as far as electronics except my 35 hp evinrude outboard has an advance connected directly to the throtal. PLEASE ANY ADVICE WOULD BE HELPFULL!:cussing:
i have what sounds like the exact same sled mine is a 1973 rc trailblazer 35 it is a tank but mine runs good when i can get it started. my primer does not work due to a rusted off sending unit in the tank.
my sled will go 50 mph plus i have never really topped it out yet.
and not boggy at all.
i think you should take out the plug and look in there with a light turn the engine over slowly and see if there is any damage to the rotor seals. if it ever had the wrong plug put in it then it will eat the rotor seal . these engines have zero clearance thats why they use a surface gap plug like some marine engines do. that would explain the bogging and blowing back out the carb under hard throttle.
check it out and let me know.
also if you know of any parts i need a recoil for mine at this time. thanks and good luck with your machine,bob
 

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Discussion Starter #8
does anyone know what your suppose to line up the timing marks to on the fly wheel on this engine. I've looked and have found no marks on the engine out side of two on the fly wheel (back side of primary clutch) and nothing to refrance to on the engine its self. usualy there is a punch mark or point of some sort to line up to but i cant find any thing. could it possibly be the plug is that point? i checked with a standerd timing lite and it seems to be close to lined up with the plug but doesnt change much as the RPMs change. is it possible that the timing advance system is not working properly? if so how do you service or where do you find the system? Bob i do have the same sled as yours Evinrude trailblazer 35 RC 1973 as far as a recoil ????????? i had a hard time finding a plug for it and ended up having the plug hole bored out to 14 mm thread to use a up to date plug. Champion stoped making the 10 mm surface gap a long time ago and no one else makes it. if you dont mind I'd like to exchange phone numbers so i could talk to you about some minor details regarding your sled. thanks for the info. Josh
 

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got it

Little did i know there was a linkage missing that opened a valve on the bottom of the motor. this hooks to the carb and was the reson that the engine didn't run. seems to run great now and even spins the track hard enough to get sideways! any one else having this problem should look into this its on the left side of engine and hooked to the throttle linkage and runs down past the starter. just a mettle rod with bends about the thickness of a mettle clothes hanger.
 

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Discussion Starter #10
bobcat 1964 did you get yours fixed i've been looking for a recoil for you and turned up nothing. I'll keep looking.
 

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in 1973 OMC built some sled with rotary engines i found one and have no clue as to what I'm doing with it my previous expirianc has been with sleds with pistons this one is a lot diffrant. i got it to run but cant get it to rev over 2800 rpm while in nutral and stuggle to make 2100 in gear. it has a top speed as of now of 20 mph down hill with a tail wind and sprays gas out the carb on W.O.T. i changed out the surface gap plug for a standard plug that made little or no differance. i tore the carb apart and its clean nothing clogged no old gunk there is only one adjustment on the carb and its center rear on top this makes vary little change even removed or tightend down compleatly any help will be apreaciated, thanks JOSH:cussing:
Have you tried ajusting the carb if it's back flowing you could have a clog in it old fuel filter read the manual to figure the right high and low could be getting to much gas
 
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