1958 Evinrude 7.5, Flywheel seized

[dltigers3]

Noob here, I just got a 7.5 for free when i picked up a 14 ft jon boat off craigslist. I tried to pull the starter and it wont move. So far I have removed spark plugs, dropped lower end, and soaked cylinders with wd40 for 12 hours. Still nothing. Is there anything else simple to try that I am forgetting, or is my next step to take apart the engine?

Also, Should I keep trying to soak the cylinders for a few more days in hope that they will free up, and should i use something other than wd40? And is there anyway to ensure there is not an issue with the motor being in gear? I have tried to pull it in every throttle position.

 

[kbait]

Re: 1958 Evinrude 7.5, Flywheel seized

If the flywheel won't turn, it's either a stuck powerhead, or gears are locked up in the lower unit. If you removed the lower unit and it's still locked, it's in the powerhead. I've used pb blaster in the plug holes (aimed 'up') and let it sit, and try to wiggle the flywheel by hand everyday. It may loosen up over time, if it's just rings rusted to cylinder walls. If it was overheated/under-lubed to seizure, you're out of luck w/penetrating oil, and you'll need to rebuild/replace powerhead. If it cannot be loosened up, I'd probably call Tim's outboard 218-682-2331 and inquire about the cost of a used/good powerhead, as rebuilding would be both time-consuming and part costs would add up quickly.

Good luck!

 

[oldman570]

Re: 1958 Evinrude 7.5, Flywheel seized

You can pull the intake port covers and look at the piston for any buildup from the motor being overheated and pistons seazed is a result of such. If there is any damage to the pistons or cylender walls the motor is scrap or will need another powerhead. If the motor is still seize after a week of soaking, bets are it is shot and will need fixed or you can part it out and sell the good parts off of it. JMO.
Oldman570

 

[1946Zephyr]

Re: 1958 Evinrude 7.5, Flywheel seized

So, you're saying that your motor is stuck? I would pull the bypass covers and exhaust cover, to get a side visual of the pistons. If they're badly scored, then no amount of lubrication is going to free them up. If your lucky, it's probaably just stuck from sitting. You may end up having to pull the head and looking inside too. Worst case scenario is some water got in there and locked it up or someone ran it with too little oil in the mix. One thing I have found on those 7.5's is over time, the inner exhaust plate will get a pinhole eaten through and they'll squirt a stream of water in through the exhaust port. Well if water sits in the cylinder, we all know what happens next.

 

[HighTrim]

Re: 1958 Evinrude 7.5, Flywheel seized

Pull the head and exhaust covers and bypass covers. Spray PB BLaster all around the piston. Every day try to budge the flywheel a bit at a time. As stated, if the rings are just lightly rusted to the bore, it will be fine. If the bearings and such are rusted, the powerhead will need to be rebuilt, or if you are not comfortable with that, replaced which is easier and quicker. Cheaper too. Post a wanted ad at aomci.org for a member in your area.

 

[dltigers3]

Re: 1958 Evinrude 7.5, Flywheel seized

Thanks for the responses. I just picked up some blaster. Going to try to move every day for a week or so. If not ill dig a little deeper

 

[nwcove]

Re: 1958 Evinrude 7.5, Flywheel seized

jmo, but id definitely remove the covers and the head for an inspection. if the cyl walls are scored and or pitted, yer just wasting penetrating oil. if its only lightly stuck, and since you have the powerhead removed, it will be somewhat easy to visually keep the pb blaster in the right spots with the head removed.

 

[rolmops]

Re: 1958 Evinrude 7.5, Flywheel seized

This would be the perfect time for some marvel mystery oil. Pour some in each hole and let it sit for a day. and see if you can jiggle it. Repeat this and check again.
It does not have to be a bad cylinder wall for this to happen. Sometimes the seal that sits on the crank shaft under the flywheel leaks and water (salt?) sneaks into the the crank case. Then if the engine is not properly winterized rust will start building in the crank case and the engine will set up. Then it is time for liberal amounts of marvel mystery oil to be poured into the crank case through the cylinders.
Very often this will loosen the rust and after a few days things will loosen up. Be very careful loosening up any bolts. force will break them ,but heat will loosen them up. I have 2 of these beautiful "holiday bronze" (red) colored machines and they both run like a dream albeit a thirsty one.

 

[1946Zephyr]

Re: 1958 Evinrude 7.5, Flywheel seized

I would definately check the inner exhaust plate for any pin holes, as well. This is usually what is the culprit for these motors getting stuck.

 

[Chinewalker]

Re: 1958 Evinrude 7.5, Flywheel seized

I would be VERY careful putting much torque on the flywheel to get it to spin. That motor has bronze babbit bearings and aluminum rods that will NOT take much of a beating. If it were mine and the above suggestions show rust or corrosion, I would strip it down and see what is salvageable. If it's lightly rusted inside, you may be able to polish the crankshaft with emory cloth. The rods, being aluminum with bronze sleeve bearings, won't rust. However, if the crank is rusted and you manage to get it turning, the rusted journals can score the rod bearing...

 

[EddiePetty]

Re: 1958 Evinrude 7.5, Flywheel seized

Before I did a lot of disassembly I certainly would remove the pull starter and try to rotate the engine by hand.......might just be a stuck pull starter or engaged starter lock-out!

 

[rolmops]

Re: 1958 Evinrude 7.5, Flywheel seized

I would be VERY careful putting much torque on the flywheel to get it to spin. That motor has bronze babbit bearings and aluminum rods that will NOT take much of a beating. If it were mine and the above suggestions show rust or corrosion, I would strip it down and see what is salvageable. If it's lightly rusted inside, you may be able to polish the crankshaft with emory cloth. The rods, being aluminum with bronze sleeve bearings, won't rust. However, if the crank is rusted and you manage to get it turning, the rusted journals can score the rod bearing...

+1.

 

[1946Zephyr]

Re: 1958 Evinrude 7.5, Flywheel seized

Before I did a lot of disassembly I certainly would remove the pull starter and try to rotate the engine by hand.......might just be a stuck pull starter or engaged starter lock-out!

Yep, this has happened more times than not. I recently picked up an old 10, that had this happen.

 

[merkdawg]

Re: 1958 Evinrude 7.5, Flywheel seized

is the motor locked up? or can you not get the flywheel to come off so you can get to the coils?

 

[dltigers3]

Re: 1958 Evinrude 7.5, Flywheel seized

So just to update, i removed the bypass and exhaust covers. There was slight rust and some gunk in there. Cleaned out what I could and let it soak in marvels for the past week. Went out today and the flywheel finally turned. Had to work it back and forth a couple times and got it to go around one full time. Put the starter back on and it seems to be working.

Now I just have to wait for my gasket kit to come in so i can put everything back together and see if it will run.

 

[RogersJetboat454]

Re: 1958 Evinrude 7.5, Flywheel seized

So just to update, i removed the bypass and exhaust covers. There was slight rust and some gunk in there. Cleaned out what I could and let it soak in marvels for the past week. Went out today and the flywheel finally turned. Had to work it back and forth a couple times and got it to go around one full time. Put the starter back on and it seems to be working.

Now I just have to wait for my gasket kit to come in so i can put everything back together and see if it will run.

Throw some pictures of the cylinders up.

 

[1946Zephyr]

Re: 1958 Evinrude 7.5, Flywheel seized

Awesome deal. Sounds like you might be able to save it. Like I said, check the inner exhaust cover plate and make sure there are no pin holes eaten through, from corrosion. These usually allow water to squirt into the lower cylinder through the ports. And of course, we all know what happens next.

 

[dltigers3]

Re: 1958 Evinrude 7.5, Flywheel seized

 

[dltigers3]

Re: 1958 Evinrude 7.5, Flywheel seized

There is a pic of the cylinder, can't really see too well though. I have now ran into two problems.

1. The upper cylinder is hitting the cylinder head once I put it back on. I reused the old gasket just to check things out, but i should have the new gasket in by next tuesday. Do you think a new gasket will give me the clearance i need?

2. The flywheel gets harder to turn when the lower cylinder is all the way out, and the upper cylinder is all the way open. Does this sound like a big issue or just something that will loosen up with use?

 

[Chinewalker]

Re: 1958 Evinrude 7.5, Flywheel seized

As I said earlier, I'd pull it apart. The fact that it turns harder on part of the revolution indicates something is binding - added to the fact that you said the piston is hitting the head. The used gasket should be fine for testing purposes. I think something is amiss inside.

Silly question - you are putting the head on right side up, yes??