1963 Merc350 in need of lots of help!

[pekstrom]

Hi everyone,

I recently aquired a 1963 Merc350 that needs lots of help. I got it real cheap so I figured I'll have a project for a year or two. The biggest issue is that it seems stuck. If I put a wrench on the flywheel nut, It doesn't turn. Well, it acts as if something slips on the inside, on step, if that makes sense. But it doesn't feel right. And I can't turn it any further. I can just go back and forth one step. So I am working on getting it opened up to see what's going on on the inside.

I'm having some trouble getting the flywheel off. The nut comes off but I haven't been able to pull the wheel off yet. I got me a wheel puller but the flywheel is stuck good on the shaft. I've been spraying Blaster PB on it for a while now.

My fear is that I'll need a new engine block. I've read somewhere that the 1963 models had some differences from the 1964 and later models. They seem to have the same part numbers though. Does anyone here know if a 1964 block would fit on a 1963 model? It is in the 1571114 - 1812753 serial number range. One would assume if another block came off of an engine in the same range, it should fit?

Thanks in advance for any info.

 

[Texasmark]

If nobody hits on this just answer it yourself with the word "Bump"...meaning you bumped it back to the top by answering. Keep it up till one of the mechanics on here catches it and answers your questions. Different folks have different attendance records as they have other things to do in life other than surf this forum....like I mostly do being retired and back into boating again. Grin

 

[GA_Boater]

You're giving a good reason why Merc outboard model years are meaningless. The change occurred between serial numbers 1812753 and 1812754. A block in the serial number range 1570507-1812753 will work for you.

2753-2754 serial number split also has different part nos. for the powerhead gasket.

According to Max Rules this change happened during what they call the 1965 model year which straddles the mechanical changes.

 

[racerone]

They are all " stuck good " on the shaft !-----The nut pushes / expands the flywheel taper over the crank taper.----This results in a tight mechanical joint of the 2 parts so that no damage occurs at 5000 RPM-----This means you need the proper puller and technique to remove the flywheel.-----I have never used PB blaster to remove a flywheel !

 

[pekstrom]

You're giving a good reason why Merc outboard model years are meaningless. The change occurred between serial numbers 1812753 and 1812754. A block in the serial number range 1570507-1812753 will work for you.

2753-2754 serial number split also has different part nos. for the powerhead gasket.

According to Max Rules this change happened during what they call the 1965 model year which straddles the mechanical changes.

Hi GA_Boater,

This is great information. Thank you very much! I have seen a block on eBay that looks nice and clean but I don't know what serial number range it came off of. I've asked so we'll see. That powerhead gasket change seems to go along with what I had read. Apparently they changed the location of some of the studs, among other things. I believe they also changed the stroke length.

 

[pekstrom]

They are all " stuck good " on the shaft !-----The nut pushes / expands the flywheel taper over the crank taper.----This results in a tight mechanical joint of the 2 parts so that no damage occurs at 5000 RPM-----This means you need the proper puller and technique to remove the flywheel.-----I have never used PB blaster to remove a flywheel !

Hi Racerone,

Thank you for the information. I have the service manual and have seen the taper on the shaft, so it makes sense that it is seated tight on there. I have a wheel puller that has a 2-point and a 3-point combo yoke, but I only have two bolts that fit the flywheel. So it doesn't pull perfectly straigt up, which I'm guessing it has to. So I am going to get an additional bolt so I can use the 3-point mode and see if that works better. This is the first time I'm attempting something like this. I have a 1980 25HP Mercury that I have spent a couple of years tinkering with and now have it running pretty good. This being a 1963 would look much nicer on the boat since it is a 1962 design. So I decided I wanted to give this a go. Besides, this will give me 10 more HP.

 

[racerone]

Is there a big thread inside the flywheel hub that can use the MERCURY style puller ?-----My 35 HP of that vintage is not on my computor desk at this time.---So can not look.

 

[pekstrom]

Is there a big thread inside the flywheel hub that can use the MERCURY style puller ?-----My 35 HP of that vintage is not on my computor desk at this time.---So can not look.

You mean a thread around where the shaft is? No, I basically had to remove some of the screws holding the ratchet to open up some threaded holes for the puller bolts. The larger holes out on the wheel don't have any threads.I attached a picture of the top of the flywheel.

 

[racerone]

On those using the 2 bolts is all you need.----A bump with a hefty hammer on the center puller bolt usually pops them of the taper.

 

[pekstrom]

Ok, I still have not managed to get that flywheel off, but I did get the crank case off so I can see into the engine, and it looks like the crank shaft, bearings, piston rods, reeds etc are ok. But when I got the exhaust manifold off so I could see into one of the cylinders, I see rust red cylinder walls. So I'm thinking a new engine block (I have seen one I think will work), new pistons and rings. I think the rest may be salvageable. I'm thinking this engine has been submerged at one point.

 

[pekstrom]

I have been fighting with that flywheel to the point that I ended up tightening the puller so tight, that the threads on the center bolt are damaged. I left it sitting tightened for several days. I have banged on it with a small sledgehammer several times. I have tapped on the flywheel. Nothing seems to work to get it off. I'm wondering if someone put locktight or something on that shaft before they put the flywheel on? It sure seems like it, but I can't imagine someone would do that. I'm pondering heating the flywheel hub up to see if it expands enough to let go of the shaft. But it is awfully close to those coils etc on the stator plate.

 

[The Force power]

I have been fighting with that flywheel to the point that I ended up tightening the puller so tight, that the threads on the center bolt are damaged. I left it sitting tightened for several days. I have banged on it with a small sledgehammer several times. I have tapped on the flywheel. Nothing seems to work to get it off. I'm wondering if someone put locktight or something on that shaft before they put the flywheel on? It sure seems like it, but I can't imagine someone would do that. I'm pondering heating the flywheel hub up to see if it expands enough to let go of the shaft. But it is awfully close to those coils etc on the stator plate.

Yup, they can get really stuck on there!
You should not hammer on the actual Fly-wheel as you'll end up damaging it.

What threads on the center bolt are you referring to? the threads on the Crank??

You can heat-up the area of the fly-wheel at the crank-area, an acetylene torch would work best as this heats it fast & will not give time enough to "transfer" the heat to damage nearby components.
(make sure to have a "healthy" amount of tension on the puller)

Make sure; you have the nut on the crank so the fly-wheel does not go flying up in the air because when they fall on the ground the magnets might/will/could break from the shock.

 

[pekstrom]

Yup, they can get really stuck on there!
You should not hammer on the actual Fly-wheel as you'll end up damaging it.

What threads on the center bolt are you referring to? the threads on the Crank??

You can heat-up the area of the fly-wheel at the crank-area, an acetylene torch would work best as this heats it fast & will not give time enough to "transfer" the heat to damage nearby components.
(make sure to have a "healthy" amount of tension on the puller)

Make sure; you have the nut on the crank so the fly-wheel does not go flying up in the air because when they fall on the ground the magnets might/will/could break from the shock.

Not the threads on the crankshaft thankfully, it is the threads on the center bolt of the puller that are damaged. It should still work though, I think. I will give it a try heating it up. I'll make sure I have the nut on the crankshaft so things don't go flying.

Thanks!

 

[flyingscott]

Don't heat it up. Put the nut back on the crank so it covers the top threads. Now get a better puller the harbor freight cheap ones will strip the bolt. Get a flywheel wrench so you can hold the flywheel in place. Then put the new puller on and tighten it as tight as you can get it ,use grade 8 bolts on the flywheel. Then tap with a carpenters hammer and put the sledge away. Hit it 5-10 times and re-tighten the bolt repeat until the flywheel pops.

 

[The Force power]

Not the threads on the crankshaft thankfully, it is the threads on the center bolt of the puller that are damaged. It should still work though, I think. I will give it a try heating it up. I'll make sure I have the nut on the crankshaft so things don't go flying.

Thanks!

Don't heat it up too much!!! it does NOT need to be "red hot" only heat-up right around the shaft area! with an acetylene torch it should not need more then 20 to 30 seconds of heating in a circular motion
a better puller may be needed, I had to borrow one a couple of times

 

[racerone]

Heat should not be needed.-----You need the correct puller !!-----Cheap " stretchy " bolts will not work.-------Use 2 grade 8 bolts and a hefty hammer on the center bolt !

 

[pekstrom]

Heat should not be needed.-----You need the correct puller !!-----Cheap " stretchy " bolts will not work.-------Use 2 grade 8 bolts and a hefty hammer on the center bolt !

I was using grade 8 bolts to the flywheel. They are both bent now. They didn't let go though. I'll look for a better puller and will try again.

 

[flyingscott]

make sure you are pulling straight up. That means at a 90 deg angle to the crank. If it pulls crooked you will never get it off.

 

[pekstrom]

make sure you are pulling straight up. That means at a 90 deg angle to the crank. If it pulls crooked you will never get it off.

Yeah, I suspect that may have been one of my problems. Since the bolts got bent the angle of the puller changed. So I need a better one. I'll see what I can find and will try again. Thanks flyingscott and everyone for all the info!

 

[racerone]

If the bolts are at an angle you are using the wrong technique !!-----Hitting it with a hammer does not work then.-----Keep the puller body from turning when tightening the bolts and center bolt !