Fuel supply fix - by accident

calboats

Seaman Apprentice
Joined
Jun 6, 2009
Messages
41
Maybe here is a fix for some fuel delivery problems. My '87 EVrude 48 got a complete fuel system re-do last fall. Ran super the last couple runs on the lake.

What I did was plumb from the tank to a screw off water filter, then to a Mr. gasket #42S electric fuel pump (at the suggested 45deg. angle and low), then to an EMPI pressure regulator (set just close to the motors normal full throttle output) at 3 psi output. At this point, I put in a new squeeze primer bulb to start things flowing. From there it went to the stock vaccum EVrude pump in the cowling, and all hose is reinforced and ethanol proof, and see through -- so you can see exactly what's happening.

Last week I hooked up the flusher, test ran the motor, lubed and checked everything out, no problems. I get to the lake, squeeze the bulb and it almost literally falls apart just as the motor starts, both ends look rotted -- and I park under cover at home. After some cussing, I just flat removed the bulb, restarted the motor, checked the fuel flow, and started looking close to see what could go wrong.

Whole new deal !! Electric pumps fuel completely into the motor, makes enough of a humm to remind me to shut it off when not needed, no more hand priming, and I can see the fuel at all times. Performance wise, it just works, no motor rpm or OB sound difference whether one or both pumps on. I was wondering about the 12v. pumps restricting the flow to the cowl pump, evidentially not at the volume used by my motor.

The stock pump is 2 1/2psi. hr or thereabouts at full throttle, my elect. is set at 3 psi., about half way on the scale so as to not overpower the factory one. Thats around 25 gph or so, well enough to run most anything I would think. Yeah, I keep a sharp eye (& sniffer?) close to the 12v. pump -- but I use the same one in my Triumph Spitfire without a problem - which is what gave me the idea in the first place. Oh yeah, I do carry a second accessory hose and bulb in a locker, juuust in case !!

I hope this helps others, and generates comments, this forum, and the expert repair members have helped me a bunch, special thanks to all.

On the Water, Cal

member of "Coots" (Oregon wood boat builders) and TSCA (traditional small craft association) boating groups. PS, yeah, still trying to find time to get the smoked lexan windows in the removable cabin top.
 

tx1961whaler

Vice Admiral
Joined
May 31, 2008
Messages
5,197
Re: Fuel supply fix - by accident

You do not need an electric pump on that motor. It is never needed. What happens if you forget to turn the pump off and you turn the motor off? You are one stuck float away from a cowl full of gas. If you feel that it is necessary to keep a sharp eye and sniffer on that pump, then you know that there is an issue with doing this.
 

calboats

Seaman Apprentice
Joined
Jun 6, 2009
Messages
41
Re: Fuel supply fix - by accident

Probably could rewire the pump to the motor hot switch, so it shuts off with the motor. Other posts have mentioned the potential problem. One thought is a momentary on push button, with the full on alternate position built in as well, probably do that today in fact !!

As I mentioned, the electric (dialed in to the proper lower pressure) is used mainly to prime the motor at start up, then I certainly can run on the stock pump alone. If that goes out, then the electric is a "get home" pump -- which was not an option before. No more squeeze bulb is the immediate improvement as far as I see it.

I have had most of the bad days concerning fuel delivery someplace along the old unviewable fuel line, or bulb, and note that many new motors have two pumps, or way more reliable systems than the old vacum pusher, sometimes a backfire or other problem away from a new diaphragm.

I'm just saying the extra pump in the line is one form of insurance that the motor doesn't run dangerously lean, that cost me a motor a few years ago, so I'm sensitive about good fuel now.

Thanks for your reply, Cal
 
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tx1961whaler

Vice Admiral
Joined
May 31, 2008
Messages
5,197
Re: Fuel supply fix - by accident

I'd love to rig a circuit that operates an electric pump switch off of the tach pulses so that it will stop the pump if the motor croaks. I have had electric pumps on cars, but they were wired to the oil pump switch to cut it off when the engine dies. Newer cars have a rollover switch to cut the pump if the car decides to take a nap on it's side or roof. The scenario that we're trying to prevent is if the engine dies, the key is on, and gas is still being pumped into a split fuel hose or stuck carb, and the starter is hit again then "poof". That makes for a bad day...
 
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