Evinrude Fleetwin 4443 Help

jpw1488

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I have a 1951 Evinrude Fleetwin 7.5 hp 4443 that I found in storage. I've done quite a bit of work recently and got it running for the first time in 40 years. Compression is 90 psi upper and 88 psi lower. I have replaced the ignition coils, condensers, points (0.020", timing adjusted with timing fixture), spark plugs and wires, carb rebuild for Tillotson MD-34B, new impeller using belt sander method, replaced broken tiller handle. I'm using lubriplate 105 for gearcase lube and seals seem to be keeping water out. Few issues now and I've exhausted the internet so here to get some help!

1) Motor starts and idles well however seems to be lacking power - 7 mph on narrow 14 ft jon boat light load. Adjusted low/high speed needles, that was max. Thoughts? Using 16:1 gas. Decarb? See photo below and number 3.

2) There was no water circulating after new impeller, but there was crud in the cooling system and flushed most of that with water hose through the flush hole in the water pump housing. It circulates, but it's hot water and kind of intermittent stream and better at full throttle. Motor runs warmer than I'm used to, but is that typical for these older motors?

3) see photo. There is a Welch plug that was partially open next to the exhaust panel on the right (exhaust side of the motor) on the lower crank case. It didn't look normal and I have a replacement so I popped it out. It's a bare metal tube with small orifice to the left and the end of the tube looks like it should end blindly, but there's several irregular openings in the end. I'm assuming that's the inside of the crank case beyond that. I thought this was where my water was going, but no water circulates though there with the hose hooked up. There's some engine oil/fuel sludge that was coming from there while running but no water. I keep thinking this may be related to either of the above problems. Not sure where to go from here.

4) Also for the impeller - how tight show it fit as far as thickness? I didn't want to over sand it. The housing closes without effort, but there's not much room in there.

Any help is much appreciated! Thanks in advance.
 

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jpw1488

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Looking at 1954 Fleetwin schematics, looks similar...is it possible that small orifice on the left wall of the tube (uncovered by the Welch plug) is the oil transfer tube to the upper crankshaft? In which case the irregular openings into the crankcase at the end of the tube would be intentional to allow fuel/oil in...
 

tomhath

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Sounds like it's running on one cylinder. A two-cycle motor starts and sounds okay on just one.

Try pulling the spark plug wires one at a time while it's running to see if it dies on one but not the other (a "cylinder drop test").
 

jpw1488

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Thanks, definitely will try that, easy enough. I'm still puzzled as to where that open Welch plug leads to. Trying to decide whether it's worth tearing the motor apart and replacing gaskets to figure out how critical it is/isn't. The schematics don't show that side of the motor at all and I can't find a picture of the motor online with enough detail to answer my question either. Anyone have any idea what the function is? (See photo).
 

F_R

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Friend, I started twirling wrenches when that motor was 3 years old. And to this day, I don't think I've ever investigated what's behind that plug. That proves one thing---it never gives any trouble. If it did, I'd have been in there by now.

My guess is it is for either the crankcase drainage system or the oiling system, or both. One thing for sure, it isn't just there by accident. My advice is put an new Welsh plug in it and don't lose sleep over it. Someday you might make the Big Discovery. and find out what it is.
 

jpw1488

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Awesome, that's good to hear! I'll plug it and put that issue to bed. Thanks for your help.

So for the cooling system...worth changing out the gaskets and giving it a thorough cleaning or call it good and use as is? Seems like exiting water is pretty hot - not sure if that's a good or bad sign! Also could a tight fitting impeller cause too much friction and loss of power of any significance?
 

jpw1488

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Update: I replaced the Welsh plug and ran the motor in a tub of water. Had to adjust my carb due to the now plugged air leak into the crank case. Ran much better until it backfired and blew the out while adjusting the carb. I replaced it with another plug and seems to be doing okay. Think my power issues may be solved. Will see when I get the motor back out on the water.
 

F_R

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Those water pumps were kind of exasperating, but worked well when everything was right. The hardest part was keeping everything properly aligned when putting it together. Everything was keyed together and held together by a flat, bowed, spring. And now we are dealing with the NLA impeller. It does have to be not too thick nor not too thin. I suppose if it is too thick it will not permit the spring to hold the housing and plate together tightly.

The water outlet hole was kind of neat. All of the water was discharged through it, so you could see and tell just how much was going through. It should squirt out at all speeds.
 

jpw1488

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I took some more off the impeller and thinned it out. I think it was dragging on the housing and causing it to jump out of those keys and the entire housing was spinning. You're right, it's a bear to get that thing lined up - need at least 4 hands to get it in there right!

Looks to be pumping pretty well now, but still seems like it's running a little hot, but I don't have anything to compare to it.

1) Do these motors run a little warm? And if the water is being pumped out the lower unit, does that indicate adequate flow/cooling or could I still have blocked passageways in the cooling system?

2) Also at idle I'm hearing something dragging up top, thought my recoil starter was engaging and loose but it wasn't. Checked the coils, they aren't rubbing. Motor was a little tilted while running because my stand is not in great shape. Any idea what that could be?
 

jpw1488

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Update:

I pulled the powerhead and replaced the exhaust cover gasket, head gasket, and lower exhaust gasket that joins the lower unit. I cleaned out the water jackets which seemed to be pretty dirty. I discovered the aluminum water baffle plate had multiple holes in it allowing water and exhaust to cross over. I made a new one. I used OMC/BRP gasket sealer except on head gasket.

It was running okay after that except when going back down to idle after running WOT for a while. I fiddled with the high and low speed adjustments. WOT seemed to run okay except not running as strong as I expected. When going back to idle after prolonged WOT the motor runs really rough, misses and knocks/clanks intermittently. I can keep it from dying and sounds better by opening up the throttle or opening high speed adjustment.

Running too lean? Too hot? Water getting into air/fuel mix? Timing off? Timing should be set correctly but I haven't checked it again since doing more work on the motor.

I checked the exhaust water baffle and gasket and both were fine. My base exhaust gasket was leaking a little and so I cut a new gasket and replaced the questionable NOS base gasket.

Took the motor out again and same thing but only after running a while. Eventually I think my base gasket blew again because motor got hot and started blowing steam out the water indicator. Haven't investigated it yet.

I did notice previously a low place on the bottom of the power head between the exiting water jacket and exhaust. I'm wondering if it's not sealing there and water and exhaust are exchanging. Seems like a tough job to lap it since the DS seal and a screw housing on the powerhead aren't flush and won't allow it to sit flat on a surface.

I have a spare powerhead from a 4447 that seems to be in good shape, but no idea what the compression is. I'm thinking about swapping them out.

Anu thoughts or ideas appreciated. Thanks in advance!
 
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