Evinrude 4hp

Our dinghy motor, a 1987 E4RCUD Evinrude has an interesting history. It was made in Belgium, spent several decades in a locker in Grand Cayman and was shipped to Toronto via DHL in a cardboard box. I would guess that before I got my hands on it that it had probably only had an hour or two of runtime. I think the previous owners would head out straight off the beach to dive. Rumour has it that the previous owner never had any luck running the engnie and spent lots of time trying to get it started – to the delight of the other residents.

Breaking the motor down with help from my stylish assistant. Never did find the 11mm socket after that.
Breaking the motor down with help from my stylish assistant. Never did find the 11mm socket after that.

When I recommissioned the motor all it needed was a throttle/cam follower as the U-shaped plastic snapped due to age.

I’ve cracked it open this fall to change the impeller and generally show the old girl some love. It’s always been grumpy at idle and the choke doesn’t stay put, meaning start-up requires a delft touch and several hands.

I don’t have a manual but I’ve found some good info in the Yachting & Boating Wold forums.

  • recommended plus are Champion QL77JC4 gapped at 0.030” ( 0.7 -0.8mm)
  • The instructions for adjusting the idle mixture screw have been published on various US forums by former OMC technician Joe Reeves and are as follows:
    (Carburettor Adjustment - Single S/S Adjustable Needle Valve)
    (J. Reeves)
    Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.
    Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.
    Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting. 
    Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburettor, do not attempt to gradually adjust all of the valves/carburettors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburettor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.
    When you have finished the above adjustment, you will have no reason to move them again unless the carburettor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburettor anyway.
  • The above is an ahhhhh-HA moment. Might explain my grumpy at idle engine….


December 1, 2015
I’ve replaced the o-rings in the fuel valve, hopefully that will eliminate the drippy fuel leak. I also followed the instructions (above) and got the engine running at a nice idle. The jet was loose so the adjustment screw was just bouncing around turning itself randomly.

I also replaced the o-rings in the choke. I replaced the impeller as it was cracking and fresh gaskets on the pump. I changed the gearbox oil, lubed all pivot points and gave it a good dose of Seafoam before running the carb dry. Finally I gave it a good wash, wax and dosed the plastic/rubber in Areospace 303.

Inside the engine covers, the 1/2″ foam rubber insulation was completely crispy, my guess is the gas fumes reacted with the foam making it brittle.  The insulation just disintegrated if touched, like dried sand, so I rubbed it off as it was getting everywhere.  I was looking for some sort of sound insulation when I spotted a dumpster at work, they are renovating a sound studio and there were 2′ square, 2″ thick acoustic tiles in the bin. I took one home and peeled it apart to thin it down. I glued it in, foil side facing the engine. I’m looking forward to a quietly burbling motor in the spring!

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