I just bought a Saito engine with a perry pump on the rear. I started the engine and the pump is leaking like crazy. [:'(] Otherwise the engine runs great.

Can these pumps be rebuilt? There is a allen screw in the middle, between the inlet and outlet, what is that for?

Thanks for the help.

From what I have seen on RCU it seems he just did a really sloppy job of putting the pump on. All the pics and drawings I have seen doesn't show the pump attached to the backplate like this.

That's a VP-30 pump, it is operated by the pressure pulses in the crankcase. The usual one for a 4s engine is the VP-20 that is operated just by the engine vibration.

If your leakage is anywhere on the black plastic part on the end of the pump, the pump is bad - there is no repair except returning the pump to Conley for exchange or repair.

On the other hand, if the leak is between the blue aluminum part and the engine back plate, that's where the previous owner has glued the pump in. Pull it out, clean everything, and reglue it.

Bill.

Sorry, forgot the crankcase vent. With the pump mounted that way I will suppose your engine is one with the crank case vent on the bottom in front, below the cam housing. You should have a length of fuel hose on it, at least 4" long. If there is no vent nipple in front you aren't going to stop the leakage in back, as the engine runs it will build the crank case pressure until it blows out at the easiest point.

Bill.

There is a vent on the bottom of the crankcase. I tried to find a rear cover for the engine but the manual says there is a pressure nipple on the cover? Is there one or is that for a different engine.

I was hoping to use the pump but if it's bad then I guess not. It is leaking from the end of the blue case. Was hoping that maybe the allen screw needed to be tightened or something simple but guess not.

Sounds like it's time for you to buy a new pump, or replacement back plate.

The back plates with vent nipples are all metal, none of the plastic ones have a vent fitting. New ones can be had from Horizon Hobbies.

You could pull the pump and make a closure plate, but I'd advise against it. The back plate also supports the carb, holding the intake pipe into the cylinder head. With the webbing cut out to allow fitting the pump it might be too weak to hold the carb correctly.

Bill.

Sorry, forgot to mention the "Allen" screw. That is to adjust the fuel feed pressure, nothing else.

Bill.

Thanks Bill,

I already ordered the replacement cover and a gasket set, should be here in a couple of days.

Has anyone ever heard of someone sending in a pump for repair and how much it costs? Just wondering if it would be worth it to send in or should I just trash it and go for a new one.

If it osts $2 to send the old pump and they give you $5 off a new one, that's still a $3 profit.

If they just sell you a new one for full price you've only gambled, and lost, $2.

Bill.