jb86

My Feedback: (8)

i have an os 120 III w/pump and 91 fs II w/pump. after leaving them for about a month, they both got clogged pumps or carbs (i.e. regulator?). would not richen. the 120 was sent back to hobby services under warranty, got a new pump. got it back, still wouldn't richen. sent it back for a second time, they replaced the pump and also the carb, i asked for it to be test run, hoping thye did and it's fine. of course they sent a note saying there was no damage to the engine, but replaced parts as a courteousy, hopefully run it this next week. i checked my 91 fs w/pump, it did the same thing. they replaced the pump, i asked for it to be test run also, somewhere along the way (probably after test running), they replaced the carb also.
they said to use a good quality ARO, but what about the pump and carb? harry higley "all about engines" states to flush the pump after every flying session w/(denatured?) alcohol thru the inlet sideof the pump. the instructions say nothing about dealing w/pump or carb, and when i asked hobby services, they had no answer.
i recently bought performance specialties ultra oil for pumped os and ys.
i determined the only choice is to run the engine atleast once every 2 or 3 weeks, even off season.
one more thing, how do i get ARO in w/a cowled os? my saito's have a tap inthe crankcase, i use to inject thru a line.
jon b

alan0899

G'day Mate,
Are you running castor oil in your fuel?
If so try using all synthetic, like Coolpower or Klotz, worth a try.

jb86

My Feedback: (8)

i run wildcat 18% totally synthetic oil, 15% nitro. i figured that would be the safest oil. wildcat uses a very good quality oil. but i guess even synthetic oil still congeals after the alcohol evaporates. good point, i should have mentioned the fuel i use. i have stayed away from castors in my 4 strokes because it could clog up the valve train, ect. w/varnish.
thanks for any input, i'd really like to figure this out, i love the engines.
jon b

alan0899

G'day Mate,
Do you run your motors dry after use?
I drain the tank, then run the motor, until it stops , then keep trying to start it until it won't fire anymore, won't take long with a 4 stroke, but should empty the pump, carb & regulator, & at least slow down any, congeling of oil.
Again, worth a try.

jb86

My Feedback: (8)

i do pump out the tanks and run my engines out of fuel. harry higley mentioned to flush the pump w/a syringe of alcohol (at the inlet side of the pump), got to be a reason he said that.
the part that i find strange is that, while on the test stand, i could prime the engines by choking, it would draw fuel (thru the pump), but the venturi would have a tremendous amount of presure built up. with just a couple turns, i'd take my finger of and fuel would spray out (clogged regulator?).
also, how do i inject ARO w/a cowled os? the vent line goes to the intake manifold.
jon b

stelios

My Feedback: (4)

I have run 2 OS FS-120 III/w pump and 2 FS-91 II/w pump for 4 years with absolutely no clogged problem. My do's and dont's are:

- Always dry your engine after a flying session.
- Have run them on full on synth/castor blend and full synth with no problem. In castor/synt blend percentages were 2% castor and 12% synth. On full synth it was 18% (Cool power).
- If WildCat bothers your engines just try some other brand.
- I have rum these engines on Modeltechnics fuel and Coolpower with no problem.
- there is absolutely no need to flush the pump with alcohol or anything else. On the contrary flushing regulator under pressure could harm itsa silicone seal.
- there is absolutely no need to inject ARO presumed that you dry the engine.
- there is absolutely no need to run the engine periodically every month. In my warbirds that these engines are installed there could be a period of 6-8 months without flying them with no problem.

All I would suggest is change your fuel and see the results. I have nothing agaist WildCat but it may not suit these particulat engines.

Stelios

jb86

My Feedback: (8)

i will look into using a different fuel, that is the only variable here. i have always felt very safe w/wildcat, i expect they use excellent ingredients. it is real frustrating to have a perfect running engine, not fly it for a month or so, then it won't work right and need $200 in repairs. thanks for the input.
jon b

d_bodary

My Feedback: (85)

I run the 140Rx and have put approx. 40 gallons of fuel thru it in two years. Always Powermaster fuels either their 15/16 blend or a fifty fifty mix of 15/16 and 20/20. and as i run the stainless rear bearing i don't even run the engine dry. I only drain the tank. At the end of the season i will run the engine dry and then run straight alchohol thru the pump inlet. Put the shipping caps back on it. After that it just sits until the weather breaks. Never had a problem with it. I've never used after run oil it. Still has the original ring and piston in it.

Dennis

jb86

My Feedback: (8)

is there a consensus that the wildcat 18% synthetic oil fuel i'm using is the culprit?
how is it that you run alcohol thru the pump (denatured alcohol?)? harry higley showed a syringe, gently injecting it into the inlet side to flush the fuel out, only a little, just to get clear alcohol to purge thru. i understand stelios, that care would have to be taken to avoid damage to the seals. but also, the carbs on both engines were replaced, i asume because of the regulator, maybe.
jon b

d_bodary

My Feedback: (85)

I use a syringe i got for fueling control line engines. Made by SIG it holds five ounces which is way overkill. They do make a smaller one. And it works fine for me. Like i said i only use it once a year. I've never tried Wildcat full synthetic so i could'nt say if it's the cause or not. Because i only do it in the Winter i just remove the cowl prop spinner disconnect the line straight to the pump and to the needle valve. once i've done that i just sit the cowl on and everything else such as the prop spinner hardware for the cowl i just put in a bag till the weather breaks.

Dennis