Thread Tools
Feb 01, 2010, 05:56 PM
Registered User Wannabe
rodneygt's Avatar
Thread OP
Discussion

Priming an engine with an oscillating perry pump


I have a perry micro oscillating pump on an os 91 surpass II. When I start it, I have to run the elect starter on it for a bit to get it to start. I can't put my finger over the exhaust to prime it because I have no pressure tap (hence, the pump). I can't choke the carb with my finger because of the cowl. I possibly could use a syringe to pressurize the tank thru the vent line but haven't tried it yet. As it is, I have to use an electric starter. I've only flown the plane with this set up on two separate occassions. How do you prime it?
Sign up now
to remove ads between posts
Feb 01, 2010, 06:33 PM
Suspended Account
I put my finger over the carb and turn the engine a few times. Or put my finger over the exhaust on a 4 cycle.
Feb 01, 2010, 07:06 PM
Registered User Wannabe
rodneygt's Avatar
Thread OP
Quote:
Originally Posted by glowguy47
I put my finger over the carb and turn the engine a few times. Or put my finger over the exhaust on a 4 cycle.
I can't reach the carb due to the cowl. There's no pressure fitting on the exhaust, which is why I'm using the pump.
Feb 01, 2010, 07:09 PM
Suspended Account
I liked your Idea of pressurizing it with a syringe , it seems like the best way to keep from having to crank the engine for 20 seconds dry till it gets fuel
Feb 01, 2010, 07:14 PM
Suspended Account
Actually using an electric starter will get fuel to the engine with no problems. As soon as the starter starts turning the engine, the pump will start pumping. I've been using them for years. First one a CG Anniversary Cub where the tank was in a lousy position.
Last edited by glowguy47; Feb 01, 2010 at 07:19 PM.
Feb 01, 2010, 08:46 PM
Registered User Wannabe
rodneygt's Avatar
Thread OP
Yeah the electric starter worked but it seemed to take forever - works quickly on subsequent flights but slow on the first one.. The only thing I could think of was installing a pressure fitting or trying a syringe. I need to re-work my exhaust set-up, so, I'll try to put a pressure fitting in my pipe or try the syringe - my wife is a nurse and can probably find me one of any size.

From another thread, here's a pic. You can see the red tinted vent line where I could attach a syringe behind the pump.
Feb 01, 2010, 09:12 PM
Registered User
b7gwap's Avatar
You could always install the choke assembly that OS puts on a lot of their 4 strokes. Then just have the control rod for it poke out the side next to your needle valve adjustment. Otherwise, I think an empty fuel bulb connected to the vent line, squeezing it to apply pressure while starting (or the syringe) might be your best option.
Feb 01, 2010, 11:37 PM
Suspended Account
I got zillions of syringes. needed them for medical problems. Fron tine to big. I'll send you some if you want. PM me your address. Probably a couple bucks to ship them. I use the big ones for all kinds of modeling purposes.
Feb 02, 2010, 08:19 PM
Registered User Wannabe
rodneygt's Avatar
Thread OP
Thanks for the offer. My wife brought me a couple of big 60ml syringes that are used with feeding tubes. So, I'll give them a try. I'm ordering some stuff for my exhaust from rcspecialties. The silicone extensions didn't last too long - just a few flights. When I get the parts installed, I'll give the syringes a try.
Feb 03, 2010, 07:49 AM
Registered User
in two strokes, fit a t-line to the crankcase, and use the syringe to inject priming fuel into the engine. Thus you have exact control over the amount of prime.
In fourstrokes there may be a problem.
I hope the tank pressurizing works for you.
Feb 13, 2010, 05:50 PM
Registered User Wannabe
rodneygt's Avatar
Thread OP
I tested the engine with my new exhaust system earlier. I used the syringe to pressurized the tank while I turned the prop. I seemed to work fine, if a bit messy - you don't have to push the plunger very hard.
Feb 13, 2010, 07:18 PM
Registered User
gerryndennis's Avatar
Rodney,
I don't know much about micro oscillating pumps, does it operate by vibration or by pressure pulses from the crank case? If it operates by pressure I have seen people turn the prop back and forward half a dozen times to activate the pump and prime that way. You don't have to go over compression, just as long as the piston goes up and down there will be enough of a pressure pulse for the pump to pump fuel to the carb.

If it's vibration that activates it I guess you are back to the syringe

Cheers

Dave H
Feb 13, 2010, 10:19 PM
Registered User Wannabe
rodneygt's Avatar
Thread OP
Quote:
Originally Posted by gerryndennis
Rodney,
I don't know much about micro oscillating pumps, does it operate by vibration or by pressure pulses from the crank case? If it operates by pressure I have seen people turn the prop back and forward half a dozen times to activate the pump and prime that way. You don't have to go over compression, just as long as the piston goes up and down there will be enough of a pressure pulse for the pump to pump fuel to the carb.

If it's vibration that activates it I guess you are back to the syringe

Cheers

Dave H
I don't know much about them either...but I'm learning. No, it doesn't run off of pressure from the crank case. You don't drill and tap the backplate. You just mount it to the backplate with two of the backplate screws. It runs of of the engine vibrations (or oscillations). Some people call them "shaker pumps".

The syringe worked ok and you only need it for the first flight, if at all.


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold PERRY Oscillating PUMP for glow punkindrublik Aircraft - Fuel - Engines and Accessories (FS/W) 2 Jul 09, 2007 01:35 PM
For Sale Perry oscillating Pump VP 20 dvk44039 Aircraft - Fuel - Engines and Accessories (FS/W) 3 Apr 18, 2007 11:18 PM
Discussion Perry Oscillating Pump Smoke - it's WORKS??? juvaknin Engines 4 Jan 04, 2007 11:09 PM
Discussion Perry Oscillating Pump Smoke - it's WORKS??? juvaknin Fuel Plane Talk 3 Jan 03, 2007 07:51 PM
muffler pressure required with perry oscillating pump ? spithungry Fuel Plane Talk 7 Oct 04, 2005 11:58 PM