HAS ANYONE USED A PERRY PUMP ON A OS91FX WITH STOCK CARB. AND NEEDLE ASSEMBLY ######

VP-30 REGULATING PUMP by perry or should I also use
vp-rnv-01 REMOTE NEEDLE VALVE I have to order both pices as nether are in stock??????####

IS there any problems with this set up or will I need new carb. as well####????

PLEASE read my last tread OS 91FX 2lemons

I tryed my air pressure in the fuel tank while on the test stand
on my other 91fx and this sure makes these motors come to life
I hope the perry pump will do the same thing?????
THIS SEEMS TO TELL ME THEIR IS A FUEL DRAW PROBLEM WITH THE 91FX motors and if every thing like tank. needle valve.fuellines,carb. etc. ar not perfict the motor will not run well
thanks agian

The owner of my LHS has been using a perry vp-20 pump on that exact engine for a long time now. Never quits on him now.
The vp-20 is a great working pump and I would recommend it to everybody.

I have 2 , both on big engines and they work perfect. One is on a O.S 1.60fx and the other on my ST 4500.

Orderd both pumps on monday (vp-30 vp-20 ) they where to be in today (friday) but they did not arrive so much for exspres mail......I was hoping to do some tests on the stand this weekend but will have to wait till next week..####
I did do some more test runs and took the stand outside so the GLOBEE tack wood work......moved tank up to centre line of carb....14x6MS prop ..omega 15% fuel ..os#8 glow....
STOCK MUFFLER = 10200 rpm
SLIMLINE PITTS = 10700 rpm
BISSON PITTS = 10850 rpm all with muffler pressure

no muffler pressure but with air pressure in fuel tank ( 1 to 2 lbs )
STOCK MUFFLER = 12100
SLIMLINE PITTS = 12650
BISSON PITTS = 12700 as this shows pressure in the fuel tank sure turns these motors on
the bisson pitts seems to rve up more but I think the slim line has better ideal and trans............... cant be realsure till the perry pumps get here......

PS IF you wought the ture story on the OS91FX please go on the perry pump web site or phone Gary Conley 1-630-858-3160
and he will tell you of the problems and some of the fixes.....
he said IM not alone with bad running 91fx he gets calls almost evey day about them....vp-30 is what he wants me to use as the vp-20 is realy ment for a 4 stroke because of the vibrations.....it may still work and stop dead sticks but the 30 will give more increase in rpms because the pressure can be cranked way up....
the real problem is the carb..it is not wellmached to the motor and this causes low fuel draw......OS knows this but refuses to fix it????????beging to sound like the super tiger 3500 motors.....

I TRYED ANOTHER LITTLE TEST I put the 14x6 prop on my old OS61FX and put it on the stand and MACS muffler (pn 6860) replaces stock muffler no more long bolts to brack off....I could hardly beleave it almost 9900 rpm with or without muffler pressure??????? with air in tank only increase about 400 to 500 rpm.....but still it was better than 91 with stock muffler and no air???????
COULD SOMEONE PLEASE TELL ME WHATS GOING ON HERE????

IN hobby services web site they say os91fx should turn a 14x6 at around 10800 but I think this is low for a 91 2 stroke????
IN the rcu review SUPER KRAFT EXTRA 300 they used a TIGER SHARK 91 motor and got alot more then that ......I guess when I orderd the SUPER KRAFT ARF last week I SHOULD have orderd a TIGER motor to go alone with it ?????????
oh well live and learn I guess :sunsmiley

THe two perry pumps came in the mail today (tue) hopfully I can do some test on the stand Tomorrow
I found out the vp-20 will not work on the test stand as the motor is tied down and can not vibrate enough ...have to wait for the super kraft 300 extra arf to test that one### the WM chipmunk does not have enough room in the cowl to use it ......

I will be using the vp-30 in the chipmunk.....with 91 fx sidemounted and slimline pitts and dubro mount it was still very hard to find room ...moved motor ahead half inch .mounted pump on firwall just below motor..away from muffler....tapped
motor in centr. of back plate for pressure to run pump....
WHEN USING THE VP-30 can I still use muffler pressure????.. what happins if I do???? what if I plug fitting and drill smaller hole????? USing 3 line dot setup for tank....dubro 16% tank..
IF I just leave 3rd line open would not fuel run out during hard manovers and upsidedown flying???? I have heard some people use it and some do not ...

I sure hope this pump fixes the 91fx proplems and no more dead sticks......I whant to get CHIPMUNK flying good before SNOW comes :boxing:

IS THEIR ANY ONE OUT THERE WHO USED A VP-30 regulating pump on a 91FX ???????????? and with a slim line pitts muffler did you hook up the muffler pressure to the tank or not

would like to get it together in the CHIPMUNK so I can fly it soon............THANKYOU.....
WHAT was your RPMs and what props ....I will use 14x6 MS....
DID THE PUMP FIX THE PROBLEMS AND MAKE IT INTO A REAL POWERHOUSE????????

Good to see you don't mind experimenting with different ideas but 1 or 2 psi is an awful lot to pump the tank up with. Muffler pressure is usually about .1psi so you've got 10 to 20 times as much pressure. What seems strange is the near 2000 rev increase. With that sort of pressure you should only have the needle opened maybe a half turn or so from fully closed and it'd be very sensitive. If you got the extra revs without adjusting the needle then you'd have been running VERY lean before.

Anyway, it seems that like most engines now the carb is really way too big for the revs it'll normally be run at. But if the pump cures it then just be happy

I use the VP-30 on an ASP Redhead 90. I used muffler pressure with no problems until it was pointed out on here that I misunderstood the instructions and was not supposed to use muffler pressure. I put a pin hole in the muffler pressure line and it still works fine. Only thing I can figure is that excessive muffler pressure must not be good for the diaphram. I wouldn't think a pitts muffler would be excessive though.

Be carefull about flooding the engine. If the engine doesn't start right away the fuel pressure will cause the carb to flood. I keep a hemostat handy and clamp the fuel line when this happens. I usually have time to unclamp the line before the engine quits.