BUflash

Hey everyone. I was just wondering if anyone has experience with the OS .61 FSR with Perry Pump and Carb? The engine I have uses the pump which is mounted in the backplate and works off of engine compression. What I need to know is the needle settings on the Perry carb for starting this engine. I've had it many years and I cannot guarantee the needles haven't moved since the last time it was used. Any input here would be greatly appreciated.

Thanks in advance!

Flyboy Dave

My Feedback: (21)

Set the slot on the disc straight up, but if you had the engine running before
and it was adjusted properly....leave it alone. The main needle at about 2 1/2
turns out should get it running. I never saw one run right with that combo, in
fact I had one, and I removed the pump....put a stock backplate on it, and an
OS 7B carb. The Guy I got the engine from never had it running right either. It
would run, but it never ran right. []

FBD.

BUflash

Well I would say these needles have definitely been messed with over the years. I tried to get this engine running about 10 years ago and had a devil of a time and I know I messed with the needles. Then I had the pump replaced and stored the engine so now I'm digging it out to finally get it going again. So with regard to the low speed disc, you're saying to close it all the way and then open until the slot is straight up? Just trying to clarify.

Has anyone else had luck with this setup? Can you mention your needle settings just so I can see if there's any variation here? I know some people swear by this engine/pump/carb combo as it is supposed to be extremely powerful.

Thanks!

NM2K

My Feedback: (14)

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That is precisely what I was saying in another post. Mine, nor anyone else I have ever met, ran really right. You were constantly chasing settings around as you flew, day after day. If there was something that I was doing wrong, I sure would like to learn it. Even today. <G>

Ditto on an HB.40PDP with pump and carb.

Flyboy Dave

My Feedback: (21)

Yep, Ed...same thing with the pumped and Perry'ed K&B. I bypassed the pump
and ran it with a stock 7B carb for about 15 years, then when it came overhaul
time I finally replaced the pump with a stock backplate.

If you like to fiddle all day long at the field, put the pump, carb, and the OS
long pipe on one, and get ta' fiddlin".

FBD.

Sport_Pilot

Must be the carb. I have no trouble setting up a Perry pump on non Perry carbed engines. Most Perry carbs are good, take a bit more tweaking than a twin needle carb, but once you get used to it you can set it easily. However I could never get the Perry carb to work right on a Fox Eagle, the original loop engine. Ran fine with a MK X carb though.

loughbd

The old OS60FSR came with a perry pump and carb and ran great. I have one. I took them off the 60 and put them on a 61. Ran great too. Not a whole lot of power gain but it ran fine and the tank was located farther away.

BUflash

Ok, so two votes for "It won't run right", one vote for "it runs well with the pump", and one vote for "pump and carb work great". Now all I need is more feedback on the needle settings. Not to discredit the advice I've already received from Flyboy Dave. I'll definitely give that a whirl! I just wanted to see if there was any more advice out there.

Thanks everyone!

Sport_Pilot

Maybe the problem is some people are using old museum pieces with old perforated pumps, others recalling using the engine when new?

Flyboy Dave

My Feedback: (21)

In theory, the pump should work fine, once you get the pressure set right.
I tried a Perry Plastic Wannabe carb once, it was junk. I don't see why the
pump and a decent carb wouldn't work.

Just wait, there will a bunch of plastic carb lovers along any minute, saying
the Perry was the best thing since sliced bread.

FBD.

Sport_Pilot

Just wait, there will a bunch of plastic carb lovers along any minute, saying
the Perry was the best thing since sliced bread.

While not the best carbs, Perry carbs are very good. Just need to make low speed mixture adjustments very small. Also the low speed mixture adjustment needs tweeking a bit more than other carbs, but not overly so. But when you get used to it you learn that the mixture indicator goes here on hot days and it goes there on cold days. The plastic seems to be very durable. Either nylon glass or epoxy glass, don't know. Not flimsy like the Irvine carb you had.

BUflash

Ok so where are all those plastic carb lovers anyway? I really need you now! Well, I test ran the engine today and there was some good and some bad. The good is, the pump seems to work great. With the fuel line detached from the carb, flipping the prop delivers a healthy dribble of fuel. When I went to start her up she revved right up with only a couple of flips. What a surprise after 10 years of sitting!

Now here's the part that has me stumped. She runs fine at idle, fine at 50% all the way up to about 80%-90% but then at full throttle she runs for about a second, then the RPMS die all the way down to almost nothing like it's flooded and then she spins right back up again only to fall back down. It'll continue like that UP-DOWN-UP-DOWN until I lower the throttle.

My first thought is that maybe I shouldn't be running tank pressure with a pump? Is this just not necessary or is it actually detrimental too? My other thought is maybe it's the glow plug or fuel. I'm running 15% powermaster fuel with an A3 OS plug.

One other problem I'm having is the needle valve wont stay put. The engine vibrations rattle it loose very quickly so I have to hold it in. Any ideas to curb that?

Thanks in advanced to all those more knowledgeable than I

BUflash

Ok well it stopped raining again outside so I gave it a shot without tank pressure and this time was MUCH better. It ran very well at high and low throttle. Just a teeny problem with the transition from low to high and high to low. It seems to load up a bit at iddle (if I pinch the line it runs for about 10 seconds before quitting). If I lean it out with the low speed disc it dies at idle. I tried moving it in EXTREMELY small increments and I just couldn't seem to get the transition to go smooth. I might just need to mess around with it another day but if any of you have experience with "fine tuning" this setup I'd welcome your advice!

Waco Driver

Are you running the Perry Pump carb with the .375" venturi and the inverted mixture screw on the top left side of the carb? This pump did not run well with the standard Perry carb with a .315" venturi.

I ran the pump and Pump carb on an OS60 FGP Goldhead for a while. During the first couple of flights each day, the mixture would keep getting leaner & leaner and I would have to land and en-richen it a couple times each flight. After the second flight it would hold the setting. The problem was that the after run oil made the pump more efficient at first and when it was displaced by more running, the pressure would drop leaning the mixture.

I too gave up on the Perry carb & pump and reinstalled the original carb and backplate.

BUflash

I do belive it is the one with the inverted mixture screw. I didn't know what that screw was for! I was looking at it this afternoon and scratching my head. The engine seems to run consistently (either rich or lean), it's just hard to get the transition smooth. Can you speak more about this "inverted mixture screw". What is it for and how does one go about adjusting it?

Waco Driver

The inverted mixture screw is a sliding valve,gravity operated, and provides a means of adjusting the mixture when inverted. If you try to use the original pump incorporated in the engine backplate, with a standard metering carb, you will find that the mixture goes excessively rich when inverted. The pump carb must be adjusted in conjunction with the pump pressure as follows.

Pump installation--
1.--Set the pump pressure adjustment screw so that the distance from the bottom of the hex is about 1/16" from the plastic body of pump. If this adjusting screw is forced closer than 1/32" from the body of pump, the pump may be damaged.

2.--The drain hole in the plastic body of the pump must face down wards irrespective as to whether the engine is vertical or side mounted. Inverted engine mounting is not recommended.

Pump carb settings--
1.--Main needle valve opened 2 1/2 turns from closed.

2.--Idle mixture disc aligned with reference mark on top of carb.

3.--Inverted mixture screw turned in fully clockwise to open valve completely.

4.--Barrel opening at idle stop approx 1/32" open.

Adjusting--

1.--Start engine, open throttle wide and set main needle for max RPM

2.--Close throttle to idle and set idle mixture disc for best idle

3.--Set throttle at 1/2 open, mixture should be very rich. Adjust pump pressure 1/6 turn at a time as required for good midrange and acceleration. (Anticlockwise to reduce pressure)

4.--Invert model,with engine running at full throttle. Mixture should be very rich. Back out inverted mixture screw until inverted mixture is as desired for clean 2 cycle operation with good acceleration from idle.

Once set up, I found that the engine held it's settings quite well provided that no after run oil was used to prevent bearing corrosion. However as stated in my previous post, after run oil definitely changed the pump pressure and made for excessive main needle adjustments for the first couple of flights each day.
I was using the perry in a biplane with a 12" prop and I found that there was no RPM increase with the large prop over that provided with the original OS carb.

Hope this helps

Sport_Pilot

One I ran that way for a while only lasted a year and a half, worked fine that way till then. Missed the warning in the instructions.

Sport_Pilot

Yep, also petroleum based after run oil will eventually ruin the pump. In fact your pump may be bad and not producing enough pressure and maybe some bubbles. Use a mix of castor and synthetic oil instead.

loughbd

Soak a perry carb in a jar of gasoline and watch what happens. You end up with a jar full of black gasoline and a lot of little metal parts.

Hobbsy

My Feedback: (102)

I have run a few of my Perry carbs on Diesel engines and kerosene does not phase them, I don't see why gasoline would.

Flyboy Dave

My Feedback: (21)

I found a way to completely eliminate problems with Perry carbs....

....use OS carbs instead.

loughbd

Says right in the instructions. Don't put 'em in gasoline. I did. Big mistake.

loughbd

I'll go along with that. OS makes some of the most rouble free and easy tuning carbs out there. That is a standard fix for the big (2000 and bigger) Super Tigres. I even put an OS 4BK on an old pre war Olhsson and it idled beautifully.

loughbd

I just realized that the header for this topic was for an OS 60FSR and his question was about an OS61 FSR. Which is it?? The 61 never came from the factory with a perry carb and pump while the 60 did. They are completely different engines.

NM2K

My Feedback: (14)

I was using the backplate mounted pumps, but it was back when they were still being sold new - in the Seventies.