Advice for a 1974 Evinrude 70 HP

[johnson76244]

Hey guys I just bought a 1974 Raycraft boat with an Evinrude 70HP (70M473) outboard engine. While I was looking at the boat we wanted to do a compression test and as we took off the engine cover we found the back side packed with sand so right away I knew the boat was submerged. I paid 1/3 of what was asked so at $500 I thought it wouldn't be all that terrible to see if I can get the engine running and the boat is in great condition. My question is I removed the top cylinder spark plug and it looks wet inside. The bendix is stuck up against the fly wheel so that makes me wonder if the motor is seized up so I'm wondering if anyone could give me some advice as to how I should proceed. I appreciate any advice in advance.

 

[racerone]

Remove the starter.----------LIKELY THE FLYWHEEL WILL NOT TURN.-------------That means that water has been inside the motor and it will be a rusted mess and all rotating parts are scrap.

 

[emdsapmgr]

It's pretty easy to pull the head off. That will give you an idea what the combustion chambers/piston crowns, cyl walls look like. You can pull the block side exhaust cover off and look thru the exhaust ports-direct into the sides of the pistons. You can see what the ringsets look like. At this point the only cost would be the gaskets to re-install these parts. Once you do a visual inspection, that will determine if you need to remove the powerhead and do a complete teardown. Racerone is correct the high polish bearing surfaces of the crank, rods and piston bearings don't like water. If they are rust pitted, they are scrap. Was this engine around saltwater? Any engine overhaul will certainly cost you more than you paid for the boat.

 

[johnson76244]

Thank you Racerone and emdsapmgr I appreciate the advice and will proceed. The engine was in freshwater. I understand that the overhaul would be more costly than what I paid but the boat is in great shape so I figured if nothing else I can still make my money back selling the boat and trailer. Either of you have an idea what it would cost to have a marine engine mechanic do the work (overhaul) I work on my cars but these motors are new to me so I'm not afraid to tackle it just don't want to do more damage and then I still have to have someone overhaul it, I'm just wondering if buying another used motor is worth it?

 

[gm280]

If you are ever going to bring this engine back to life, DON'T turn the flywheel until you can see what's inside. Maybe you'll get lucky and the inside isn't toast. But turning the crank can lead to more damage to everything if there is anything left to salvage. You could get lucky and the crank and bearings and such didn't get rusted and ruined... Cross your fingers and look see. At this point what is there left to lose...

 

[racerone]

Whether it is worth fixing depends on finding good used parts that may need to be replaced.---------Shops rarely will want to take the time to find the parts for you.-------------New parts if available will be astronomic in price.

 

[emdsapmgr]

There should be tons of good, used parts in marine salvage yards around the country. This was a popular engine at the time. These early versions were the smaller 49 cubic inch models.

 

[johnson76244]

Thanks for the advice guys I certainly appreciate it. I'll go ahead and do the inspection after crossing my fingers of course then proceed from there. I'll put another post on what I find. Just wondering how hard is it to do a rebuild on this engine if I can get the parts? I've looked and it does look like I can get parts for the engine but Racerone is correct it could get pricey really quick but then again what is a good used engine going to cost me less than a rebuild if I can do it myself?

 

[boobie]

Do what was suggested above and get back to us.

 

[johnson76244]

Will do.

 

[BigB9000]

I would imagine big $$$ to pay a shop to do it.

Where are you located anyway?

 

[johnson76244]

I'm north of Fort Worth, TX. From reading a lot of forums I agree it would be some big dollars.

 

[emdsapmgr]

If you are somewhat mechanically inclined, consider doing the work yourself. You can still get the original factory service manual for your year engine from the original publisher: outboardbooks.com The only one to buy if you get a service manual.

 

[johnson76244]

Hey guys I removed the cover for the carbs and other than a little surface rust the insides look good. I removed the spark plugs and each cylinder looks good except no. 2 that has some water still in it but looks ok. I tried to remove one inspection cover bolt and it snapped so I didn't remove any more. I sprayed Seafoam in the carbs as well as in the spark plug holes then turned the motor it would move at first but then did and turns easy.

I appreciate any advice on next steps but these are my thoughts:
1. Fog the engine by hooking up the starter again and use it to crank the motor.
2. Check compression.

I did find some of the wires in the bank along the powerhead to be broken and corroded so I believe the engine wouldn't run until I fix that. Does anyone know of a link that will provide a schematic of the wires and how they should be attached I did find one that was not attached the end was taped to another wire.

I do have oil coming from the impeller so I don't know if that is normal or another issue. At this point it seems promising so what do you guys think?

Thanks a bunch...

 

[emdsapmgr]

For a color wiring schematic try the first post on this page, the "top Secret files." It has some color coded wiring diagrams for Johnson/Evinrude. You may not find your exact year, but it should get you close. There is also one in the back of the factory service manual for that year. If the oil from the lower unit is black and tarry-looking it's probably ok. That is unburned exhaust residue from the midsection. If it's clear or caramel colored, check the lower unit gear oil -to be sure it is full and not contaminated with water.

 

[Chinewalker]

If you have surface rust on what is visible, you likely have surface rust on the bearings that you can't see from the intake side of the crankcase. Even if you do get this motor running, it likely won't have a very long service life and will probably come unglued in fairly short order...

 

[johnson76244]

emdsapmgr - yes the oil is black and tarry-looking. There was enough wire to put new ends on and put where they were supposed to go. Just need to pick up a rectifier because that wire cannot be saved. It's getting there but very slow not many hours I or my son can devote but we work on it whenever we have time. We took the flywheel off inspected and cleaned and everything looks good up there. I do need to get a manual also but wondering if you would happen to know what the torque spec is on a 1970 70HP Envinrude, I think it should be around 100-105 ft lbs but it sure came off easy I used an impact but still if it were 100 foot lbs it would have taken a couple of impacts. Thanks again for the advice and info I really appreciate it.

 

[emdsapmgr]

That is the correct torque for the flywheel nut. Same as the V4 crossflows.

 

[volchara]

Hello! I'm from Russia.Stumbled on your site,he recently purchased the exact same motor 1976 ,problems with repairs I don't have,we have problems with spare parts.The engine is very simple and don't be afraid to disassemble,as far as I understood through an interpreter,the motor was*drowned*,don't worry,if drowned not working-nothing terrible,the main thing that he was not under water for a long time and it is not washed sand but it's not terrible.Do for themselves and realized they were very sorry,disassemble the unit,podbirayas to the bearings and inspect them for rust but once disassembled buy new bearings ,reassemble and enjoy the work of man.If you need have questions that I know the answer,at the moment my motor completely disassembled and can do photo for illustration purposes,to you it was easier to disassemble.I'm sorry I got in Your topic and it may be that it is unclear wrote but I write through a translator online.In part of electricity can also make a photo on my motor.Yours sincerely Andrew.

 

[johnson76244]

I don't see the "top Secret files" in the first post. Thanks