FS-90
#1

I am wondering if I still can get any parts for my FS-90 four stroke engine. Is there anyone that still has any parts? The engine still runs good, however I think I would like to rebuild it to freshen it up some. I think I bought this engine in the early 1980's.
#3

My Feedback: (11)

Because the O.S. Max FS-90 has been out of production so long, we'd not have parts, nor would O.S. Unfortunately, we'd not know who might have any parts. Please check with the dealers who sell parts and engines to the collectors' market. They usually advertise in small ads in the back of the model magazines.
#4
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Bax,
I have an OS FS-90 Surpass. It has the silver valve cover. I bought it used some time ago. I do not know how old it is. It was installed in a used Hog Bipe I bought from a hobby shop. It starts really well and runs smoothly but it does not seem to have much power or have much compression. When turned over by hand it offers very little compression. I am comparing this compression feeling to my OS FS-91 Surpass 2, black valve cover, that I also bought used. How do I go about either rebuilding it or having someone like OS (?) professionally rebuild it? Do you think the cost of a rebuild is too close to the cost of a new one to bother? Any guidance, suggestions, or opinions regarding this matter would be greatly appreciated.
Airroy
I have an OS FS-90 Surpass. It has the silver valve cover. I bought it used some time ago. I do not know how old it is. It was installed in a used Hog Bipe I bought from a hobby shop. It starts really well and runs smoothly but it does not seem to have much power or have much compression. When turned over by hand it offers very little compression. I am comparing this compression feeling to my OS FS-91 Surpass 2, black valve cover, that I also bought used. How do I go about either rebuilding it or having someone like OS (?) professionally rebuild it? Do you think the cost of a rebuild is too close to the cost of a new one to bother? Any guidance, suggestions, or opinions regarding this matter would be greatly appreciated.
Airroy
#5

My Feedback: (11)

Your FS-91 Surpass (there was no FS-90 Surpass) is from the first series.
Low compression can be caused by a bad piston/ring/liner fit. You may only need a new ring, or any/all of the three. The piston, ring, and liner together will cost about $100.00.
Low compression could also be cause by a bad valve fit. We clean the cylinder head thoroughly and use a bit of toothpaste to lap the valves. If that doesn't work, you may need new valves or a new head with valves. Head with valves is about $120.00, valves only are $70.00 for the pair (with springs and retainers). Valves only will cost about $10.00 less than the full assembies.
If we do the rebuild, add about $30.00 in labor or so, plus postage.
A new FS-91 Surpass II w/o pump runs about $280-$300 from many retailers.
Low compression can be caused by a bad piston/ring/liner fit. You may only need a new ring, or any/all of the three. The piston, ring, and liner together will cost about $100.00.
Low compression could also be cause by a bad valve fit. We clean the cylinder head thoroughly and use a bit of toothpaste to lap the valves. If that doesn't work, you may need new valves or a new head with valves. Head with valves is about $120.00, valves only are $70.00 for the pair (with springs and retainers). Valves only will cost about $10.00 less than the full assembies.
If we do the rebuild, add about $30.00 in labor or so, plus postage.
A new FS-91 Surpass II w/o pump runs about $280-$300 from many retailers.
#6
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I have an older FS 90. Engine runs great. The problem is that the throttle is on the wrong side for my plane. Can the throttle control be moved to the other side on this engine? Or do I have to modify the plane. The engine does not do well mounted inverted.
#7
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Corsair, I have the same engine which I was able to get the critical spares I needed. That is:
Piston ring OS part no. 45403400 (also suits 160 twin) - still available from OS but I had to wait month to get it from Japan - I bought one about 18 months ago.
Front crank bearing R6Z (R6ZZ with one shield removed).
Rear Crank bearing 6001ZZ (take out the metal shields).
Cam bearings are also available.
Here's a link to an Australian bearing supplier who list many bearing replacements for RC model engines http://www.minibearings.com.au/products_index.html.
Good luck!
Piston ring OS part no. 45403400 (also suits 160 twin) - still available from OS but I had to wait month to get it from Japan - I bought one about 18 months ago.
Front crank bearing R6Z (R6ZZ with one shield removed).
Rear Crank bearing 6001ZZ (take out the metal shields).
Cam bearings are also available.
Here's a link to an Australian bearing supplier who list many bearing replacements for RC model engines http://www.minibearings.com.au/products_index.html.
Good luck!