Topic: 1963 EVINRUDE 40 HP EVALUATION – Antique Outboard Motor Club,Inc

This topic has 19 replies, 11 voices, and was last updated 9 years, 6 months ago by retroman.

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December 8, 2015 at 3:23 am #3124
retroman
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Hey Guys,
I purchased a 1963 Evinrude 40hp for somebody on this forum for $125 about a year ago. I finally got to play with it and am having a ton of fun. I did the very basics, a compression test, and it checked out. The LU was off, so I inspected the impellar, looked good so I reinstalled it , put the LU on and fired it up. Started up but didn’t Idle great. So I pop the flywheel off and inspected the magneto. Coils looked good, so I regapped the points and replaced the wires. Took apart the carb, cleaned it, treated the float with Butyrate dope. Took the thermostat out and made sure it opened when hot, reassembled and I fired it up again. Much better!
So I installed a new impellar and mounted the motor to my 1961 Dorsett Eldorado (14ft). I took it out this weekend for a test run. At the dock I noticed steam or exhaust rising into the engine cover, the gasket around the exhaust housing looked good but I guess some dirt got in there causing a leak, easy fix. For testing purposes I removed the engine cover. I open the throttle and got up on plane instantly, I’m at wide open throttle and she runs great……..for about a minute, Then cuts out and dies. She fires back up and I’m on plane again, WOT and sure enough, she dies again. Well third time is a charm, she fires right up and I lovin life at WOT and sure enough, she dies again. She fired right up and I idled back to the launch ramp with ease. I think I have this figured out, but before I tear into this motor I figured I would ask you guys for your opinion/diagnosis.
Thanks in advance I appreciate it.
Jim
December 8, 2015 at 3:31 am #28207
wedgie
Participant
Not getting enough fuel? ❓
December 8, 2015 at 4:07 am #28209
Mumbles
Participant
Yup, fuel pump diaphragm is probably dried out and hard from old age.

If the pump is rebuildable, you can get diaphragm material here.

http://www.pfs-ware.com/Parts/OllieParts.htm
December 8, 2015 at 11:09 am #28220
retroman
Participant
I forgot to mention I rebuilt the fuel pump. Its definitely a fuel problem, but Im confident its not the pump.The pump works fine at slower speeds. Also if the diaphram had a hole in it would burn an excessive amount of fuel and possibly foul the spark plug in the cylinder that creates the crankcase pressure that powers the fuel pump. Thanks for the input. I do have a diagnosis, Im looking to see if anyone comes up with the same diagnosis I did.
December 8, 2015 at 12:18 pm #28225
frankr
Participant
US MEMBER PAY BY CHECK
My suspicion is it is sucking air at some point along the fuel line between motor and tank. Or at the tank outlet itself. But before I commit to that suspicion, we should know–can you keep it running by pumping the fuel primer bulb?
December 8, 2015 at 1:06 pm #28227
jerry-ahrens
Participant
US Member
I have also found the aftermarket fuel line connectors are notorious for sucking air.
December 8, 2015 at 2:43 pm #28231
fleetwin
Participant
US Member
Well, there are other types of fuel pump failures than a leaky diaphragm that would cause low fuel pressure. BUT, air leaks/restrictions can disguise themselves as fuel pump problems as well. How about the fuel supply? Is it fresh, perhaps there is some water in the fuel causing the engine to stall out. How about the high speed jet, did you actually remove and inspect it?
Finally, be sure the engine isn’t overheating causing the stalling at high speeds.
Perhaps there isn’t enough oil in the fuel causing the engine to seize stall at high speeds, sure hope I’m wrong about the overheat/low oil seize possibilities!
December 8, 2015 at 11:20 pm #28250
retroman
Participant
wow, thanks guys. My doom and gloom personality has me think of everything but the obvious. Im thinking crank shaft seals, that the engine is leaking compression out the seals and it cant supply enough pressure/suction to run the fuel pump at higher RPMs. But, in fact the fuel connector was sucking air now, that I think about it, I had trouble priming the bulb and heard pressure leaking out of the fitting, I switched tanks and didnt give it another thought.Thanks Jerry, the obvious doesnt occur to me, I appreciate you pointing that out in big, bold type. Im gonna give it another shot on Saturday. I’ll keep you posted.Thanks to everyone who took the time to post comments. You where all very helpful.
Jim
December 9, 2015 at 10:14 pm #28294
fleetwin
Participant
US Member
Don’t overlook the simple stuff!
December 9, 2015 at 11:31 pm #28300
johnyrude200
Participant
Don’t overlook a spec of dirt/junk in the high speed orifice or any of the aforementioned air leaks (which there are plentiful ways for that to happen). Old fuel line from pump to carb is downstream of the fuel pump filter and could clog up the orifices/carb passages.

I’ve seen intake bypass cover gaskets with tiny holes suck air. Yesterday had a 9.5 that was running lean, and it was all attributed to a spec of old fuel line occluding the high speed orifice. Remove, blow out with compressed air, and voila, the motor runs like tops again. Motor ran OK at low speed, but at WOT, within 3-4 seconds would stall out and die.

I’m leaning away from this suggestion – but if the condensers are on their way out, that may present the way you’re talking about but could be ruled out pretty easily on the fly with an air-gap spark tester after the motor stalls out…and it shouldn’t start back up immediately, would take some time to get it up and running again.
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