1957 evinrude pops out of gear

I have a 1957 fleetwin 7.5 horsepower. It likes to pop out of gear when the engine is idling. Holding a finger on the shifter was all it took to keep it in gear. At anything more than idle it was fine. Lately its been popping out of gear under power. It popped out once under full power and thats when I decided to park it until I fixed it.

I've read some posts and it seems like it may be a shift linkage adjustment issue or the shift dog is worn out. Since the problem has been getting worse I'm leaning towards the shift dog.

What I'm looking for is: an online parts store that has lower end parts listings for this model. So far in my searching I haven't found a place that does, they either stop in the 80s or in the 60s. I'm hoping someone knows where I can find parts.

Re: 1957 evinrude pops out of gear

Here's my thoughts on this:

I think your shifter was out of adjustment the way you describe it, and this misadjustment has led to a bad clutch dog/ forward gear engagement ears. You can try adjusting the shifter first and see if that cures both idle problems with gear disengagement and full power. If not, the only thing to do is to pull the powerhead to disconnect the shift rod, and pull the lower unit to check the clutch dog and gear ears for wear. It's possible you can fix the shifter adjustment properly, and flip the clutch dog to get some more use out of it, but a lot of the time it's not just the clutch dog, but the gear engagement ears that are worn as well. If you have to get into the lower unit, it would be helpful to show the clutch and gears to someone knowledgeable to look at them since it doesn't take a lot of wear to make it do what you describe at full throttle. There's also a "shock absorber" in there that could be considered as a culprit.
Good luck,
JBJ

Re: 1957 evinrude pops out of gear

Thank you.

I've already had the engine and lower end taken apart. I had to replace the water pump impeller, ignition system (points, condensers and coils) and then I honed the cylinders and cleaned out the ring grooves because it had poor compression on one cylinder. One cylinder was 75psi and the other was 30psi before honing. After honing they both would do about 85psi.

When the lower end was apart I looked at the gears and the engagement points looked good, they still had square corners on them. The shift dog, the half moon piece that slides between the 2 gears on the shaft, had the corners on the side that faces the gear for forward a little rounded. I was not aware that I could flip the shift dog. The shift linkage was all solid pieces I didn't see anything that would act as a shock absorber.

I used 80W-90 in the lower end when I put it back together. I'm not sure what it needed but the 80w-90 I had looked about as thick as what came out. If its not the right oil I'd appreciate knowing what is correct.

BTW... I may be mistaken on the year of the engine. Apparently, the engine I have, 7.5 hp Fleetwin, its model year is the first year evinrude put reverse on a 7.5 horsepower engine.

Re: 1957 evinrude pops out of gear

I have a '55 7.5 evinrude with reverse. They sold a bunch of them and probably that's a good guess at what you have. the shock absorber is above the pinion gear and probably isn't your problem. If it were me, I'd get the shifter adjusted and see if it solved my problem. If it is still coming out of gear while just idleing, either it's out of adjustment or you have some slop in your bellcrank connection under the powerhead most likely. If still coming out of gear while WOT, you might try flipping the clutch dog. You might get a bunch more tanks of gas out of it that way. Marine grade 80w-90 is fine. Regular automotive grade is fine as long as the lower unit doesn't leak at all, the marine grade just has additives that help if a little bit of water gets in. I think it has an emulsifier in it. here's a pic of my fleetwin with paint color that is close to original. Does it look like yours? If not, you could always post the model number on the tag on the transom bracket and someone can tell you which year model it is.
Good luck,
JBJ

BTW, impressive work on the compression/honing! 85psi is great on a '50s 7.5hp. I'll bet it runs nice. If you don't mind me asking-- did you use a brake cylinder hone and just re-use the old rings? Mine have about 80psi on my '55 and '57 7.5 and run good.

Re: 1957 evinrude pops out of gear

Thanks again for the information. I think you may be on to something with the shifter bell crank. The opening where the shaft comes out to the shifter handle has a crack in it, that could make it have some slop, maybe enough to pop out of gear....... have to look into that.

The engine runs like a dream. Once its warmed up it can idle down in gear so slow you can count how many times the flywheel turns. It starts so good, I swear I could grab the flywheel with my hand and spin it and the engine would fire up, but I won't, I'm afraid it will eat my hand. And going slow its so smooth and at full power it hums. Its so quiet and smooth from the springs on the transom mount. My friend has a 3.5 gamefisher that is basically a 2-cycle air cooled lawn mower engine mounted on a shaft with a propeller on the end. Its super reliable, one pull start every time but it is loud and vibrates the whole boat, probably scares away the fish too.

We've been using automotive 80w-90 oil in the lower end. We change it after every time we take it out because it gets milky. I have most of a gallon jug of 80w-90 from when I changed the transmission oil on an old truck I used to have. When thats gone I'll invest in a seal kit and marine 80w-90.

Your engine looks exactly like the one I have. Except mine doesn't have a cowl, and the recoil is broken. my friend and I got sick of getting whipped by the knot when we would wrap a rope around the flywheel so we made another one from lawn mower parts. I took the starter cup off an old push mower and drilled holes in it to match the flywheel. Then mounted the whole blower housing with the recoil to the top of the evinrude using the factory recoil mount points. We had to make brackets out of extruded aluminum angle stock from the hardware store. My friend and I call it "darth vader" because the blower housing kinda looks like a helmet.

The engine had poor compression on one cylinder because you could feel the roughness on the cylinders from the pitting. We took the whole engine apart down to a pile of parts and nuts and bolts. We cleaned and polished everything with nylon brushes and rags. They don't build things like that anymore. (Ive never seen a 2-stoke with brass bearings for the crankshaft.) I used a regular full sized hone on the cylinders, I had to close it almost all the way. I honed a long time on each cylinder. When I was done they felt super smooth and looked new except for the pits. We used the old rings and then put the engine back together with silicone gasket sealer in all the spots we had gasket issues taking it apart. We also took out the check valve thing on the reed plate so it could be hooked up to a pulse type fuel pump (again, a lawn mower part) instead of a pressure tank and it works great as long as the fuel from the tank can gravity feed to the pump. We made a bracket that hold the tank up near the gunwale and the pump just hangs from the hose near the bottom of the boat.

I think next time my friend and I get together to work on the engine we will check the adjustment on the shift linkage and flip the shift dog and see what happens.

Re: 1957 evinrude pops out of gear

You are quite ingenious with your motor fixes! I have a few tips if you wouldn't mind......
1st, you should go on aomci.org and place a free ad for the recoil parts and cowl that you need. Someone is bound to have one laying around which they'll send you for a reasonable price.
Also, that motor was originally designed for 16:1 fuel/oil mix, and due to the pitting on your cylinders, I'd definitely use that much oil if it were me.
Last of all, if you need to have the tank elevated, then your fuel pump is not functioning. You need to see what the problem is. On my '55 7.5, I'm using a briggs and stratton pulse vacuum pump and it works fine. It should put plenty of vacuum to suck fuel from your tank with the tank on the bottom of your boat if it's mounted correctly. You either have a vacuum leak in the hose or your check valves under the intake manifold are not correctly done in order to create vacuum out the intake nipple for your pump. You should take all the check valves out, and use a vacuum line plug to block off one of the 2 holes where the check valves went. There's an article with pics on duckworks.com If you haven't seen the article just holler and I'll post a link to it.

Those are really good motors. I'll bet yours does crank really easy and idle smooth with 85psi!
Good luck,
JBJ

Re: 1957 evinrude pops out of gear

I took both check valves off. That may be why the pump isn't pumping well. I'm also using a briggs and stratton pump.

I've been using 20:1 mix with outboard oil.

I will go check out aomci.