1975 Mercury 650 blue band - Abandoned, but brought back home

[ruahusker]

Long story short, I have had this boat (15 foot tai-hull) for about 15 years and had some good times, but it ended up in a storage yard for the better part of the last decade. I decided to replace the tires on the trailer and bring her home to see about restoring it to sea(lake)worthy condition.

Several years ago the cover got ripped to shreds in a storm so it has essentially been completely in the elements.

I got a new battery and had to hook directly to the motor because the cables are pretty much corroded due to weather. I put some oil in the lower, got some fresh fuel with oil mix, and decided to see if it at least has some spark of life before I dump some money into getting it back up to par.

When it turns over it is very slow, almost like a weak battery. The battery is a brand new 550 CCA marine battery, so I don't think that's the issue. They say a picture is worth a thousand words, so I decided to take a quick video. Any ideas where I go from here?

Thanks

 

[racerone]

Pull starter apart for inspection and testing.-----Not sure how then ask.----Don't spend any beer tokens until you determine condition this engine-----If water got inside and on crankshaft bearings it could all be scrap.

 

[merc850]

Charge the battery fully and try again and check the voltage while cranking it should only drop a few volts.

 

[ruahusker]

Pull starter apart for inspection and testing.-----Not sure how then ask.----Don't spend any beer tokens until you determine condition this engine-----If water got inside and on crankshaft bearings it could all be scrap.

Sounds good. Tomorrow I will have my voltmeter so I will also check voltages since wire corrosion is also a concern. I will go ahead and pull it if that checks out. Thx.

 

[ruahusker]

Charge the battery fully and try again and check the voltage while cranking it should only drop a few volts.

Yeah, sounds like a plan. I have my voltmeter tomorrow so I will check and see if it drops much. Also, I might pull the starter to check it and see if it is an issue. It is spinning though and not making any weird noises, so my initial thought is that it could be low voltage somewhere.

Thank you

 

[merc850]

Hook the neg cable to the block and touch the pos to the post on the starter that hooks to the solenoid. It took me 10 mins to boost my car battery due to bad connections.

 

[ruahusker]

Good morning. I went out with a new strategy this afternoon. I hooked up the neg directly from battery to the block, and the positive to the post on the starter. It turns over just like yesterday. Slow and doggy. Voltage on the battery is 12.6v without turning over and just under 11v while trying to turn over the engine.

Since the fly wheel is fairly hard to turn over by hand, I wanted to make sure it isn't corrosion on the crankshaft or something, I removed the spark plugs and it turns freely with very little resistance. I put a little bit of penetrating oil into the cylinders for good measure.

I am starting to think the starter is shot. I guess the next step is to remove the starter. One thing, it is spinning hard enough initially to pop the gear up to the fly wheel, but it just doesn't have any oomf. I know you can buy a non OEM starter on amazon or elsewhere for about 70 bucks, so that might be my next step.

Any other suggestions? I will probably pull the starter a little later today.

Thanks

 

[merc850]

Take it apart, the brushes may be worn out and a repair shop might be able to fix it cheaper than buying a new one. I also noticed the shift and/or throttle cables have splitting casings which is not good and there's some material in the airbox that looks foreign.

 

[ruahusker]

Take it apart, the brushes may be worn out and a repair shop might be able to fix it cheaper than buying a new one. I also noticed the shift and/or throttle cables have splitting casings which is not good and there's some material in the airbox that looks foreign.

Will do. Headed out right now to take it off. Yeah I am going to have to replace the throttle and shift cables, they are in horrible shape but seem to surprisingly still work. My plan is to get this to at least run for few seconds. IF I can get it running, will replace the impeller, electrical wiring, plugs, fuel lines, throttle and shift cables, etc. There is ALOT of corrosion. If I didn't have a little bit of sentimental attachment to this thing I would probably be scrapping it or selling for parts. If I can get the motor running reasonably cheaply, I will work on the aesthetics later.

I will update when I have the starter off.

 

[racerone]

Do a full evaluation of this motor before spending any beer tokens.-----Post the compression numbers here.-----Do a spark check as well.-----Pull it over with a rope for the testing.----Maybe remove bypass cover to look at pistons / rings.

 

[ruahusker]

I am trying to pull the starter but having some issues getting it out. Do I need to take the fly wheel off to get to the other side of the mount? Here is a photo of where I am so far. I apologize, I am very much a non mechanic, but if this has a chance of working out, I will have to do 95% of the work myself. lol. Should be a fun project.

 

[racerone]

Flywheel does not need to come off.----It appears to be 4 bolts and those 2 brackets come off.----Then starter might fall out.

 

[ruahusker]

OK. I got the starter out. I think I removed some bolts unnecessarily, but oh well , I got it out. Here are a few pics of what the start looks like taken apart. I have no idea if this is horrible or if anything can be told. I will say when I try to spin it by hand, if I do it quickly, I get a bit of a bad bearing (grinding) type sound.

I have a compression tester on the way. I probably won't get it until Tuesday. I will post numbers when I receive it.

Thanks all of your help so far.

 

[racerone]

Use a digital ohmeter.----From commutator to the shaft should read infinity.

 

[merc850]

The brushes look OK - is there any play (wobble) on the top bushing? if so this can affect the operation. Here's a tool that helps to assemble it.

 

[flyingscott]

Take the lower unit off and see if it frees up.

 

[ruahusker]

Thanks for all the responses so far. Here is where I am at:

I decided to go ahead and replace the starter. It has a manufacture date of 1974 so I decided after 48 years, it was probably due, plus it will help with my compression test to have a functioning starter.

Ordered compression tester
Ordered replacement impeller
Ordered some carb and choke cleaner
Ordered new starter for $57.00

When I get the new starter in and compression tested, I will post my numbers to see if it is worth going any farther.

Thanks!
Steve

 

[ruahusker]

Take the lower unit off and see if it frees up.

I will be taking it off when I get my replacement impeller. Will give it a go and let you know.

 

[ruahusker]

Okay. I got the new starter and compression tester. The starter appears to be the main issue that I was having in the original post. With the new starter it turns over rapidly and with little effort. It didn't start, but I didn't mess with it long enough to worry about that. I just wanted to verify it was indeed the starter.

Now for my second potential issue. I tested the compression on each of the cylinders. Top cylinder is 105psi, middle is 130psi, and bottom is 130psi. The engine was cold, and I did not add any oil to the cylinders manually. I assume my gauge is accurate but the difference between top and the other two concerns me. Realistically is this much of an issue or is it to be expected on a 48 year old motor? Any chance it gets better after I get it to run for a bit and the rings perhaps lubricate and expand a bit?

Next up, I am going to change the impeller and when it is a bit warmer, get the muffs out and see if I can get it to crank over for real.

Oh, one more thing. I have a mystery part that I need help identifying. ha. it fell from somewhere above the carb when I had unscrewed several things and they were dangling there. I will post here in a bit.

Any info on the compression would be appreciated. The serial on my motor is 4139949, so I think that makes it a 1975.

 

[racerone]

See post #10.-----Now remove bypass cover to look at the piston / rings on top cylinder.----Not sounding good here.