SRQFlyer

My Feedback: (17)

Hi all,
I'm posting this here because you classic pattern guys are bound to be the most knowledgeable about this engine. I actually have three SFs and this one makes four. This one has a pump which leaks (just a little) from the hole in the one adjustment screw. Here are my questions:
1. Is it possible to repair these pumps? 1a. If so, is there a "specialist" who can do it. I actually took one of my others apart for cleaning (and it still works), but I wouldn't know what is wrong.
2. Is there any source of parts for them anymore?
3. Has anyone seen this problem before?
4. Is it possible to just use a Perry pump and a regular SF backplate.? I thought I read of this many years ago, but can't find it now.

Thanks in advance for any and all help - and HAPPY HOLIDAYS!

Jim

countilaw

I have several of these engines and most of the pumps still work on them. The engines with broken pumps are just in storage for parts.

1. Is it possible to repair these pumps? 1a. If so, is there a "specialist" who can do it. I actually took one of my others apart for cleaning (and it still works), but I wouldn't know what is wrong.
OS Max has always warned modellers from taking the pumps apart and to never tamper with the adjustment screws. That is why you find a dab of paint on the adjustment screws.

2. Is there any source of parts for them anymore?
Basically, there are no parts for these pumps. And most of the diaphrams in the old one's you will find will have hardened and cracked. This also goes for old perry pumps.
3. Has anyone seen this problem before?
The diaphram has cracked and is leaking.
4. Is it possible to just use a Perry pump and a regular SF backplate.? I thought I read of this many years ago, but can't find it now.
Yes, this is the usual fix for using the .61 SFP. If you can find an old back plate, it will work fine.

SRQFlyer

My Feedback: (17)

Thanks! Sort of what I feared as to the parts, etc. I guess I'll just try the Perry route, as I have a spare, plain backplate. I guess I should I block off the "sense" port on the carb vs. just leaving it open. I'll experiment on that one. I also think I better test my other OS pump unit and the two Perry pumps I have for dried-out diaphragms. I also have a Robart "Super Pumper" that has a third line for excess fuel return to the tank. Looks like I'll so some experimenting on my next trip to the field.
Thanks again,
Jim

8178

My Feedback: (17)

From this picture I do not think the diaphragm is rubber http://sceptreflight.net/Model%20Eng...%2061SF-P.html If it runs Ok and is just leaking from the adjustment screw threads, I'd seal the screw and call it good. DO NOT turn the screw, just seal over the top.

SRQFlyer

My Feedback: (17)

I'll be doing some testing soon and this will be the first thing I try. I'm concerned that the leak is coming from the hole in the middle of the adjustment screw and that may be atmospheric reference for one of the diaphragms. I'll try sealing it and see if it still runs good. Otherwise, I'll try to determine how much is leaking - I may just route it "overboard" if it's only a little.
Thanks for the idea,
Jim