did as uch reading as i could but stuck.1966 500 thunderbolt

[tkq23111]

I have been doing a lot of reading and allmost there.Ill start from the begining and apoligize for speeling I suck at it.lol.I have a 50 hp serial number 2011810 mercury thunderbolt ,year 1966 i belive.When I bought it .It wouldnt go over 10mph.the guy i bought it from said it had the wrong prop on it .the right one feel in the river.I used it for a season and delt with the 10mph.This season the starter whent .I did some reading on checking voltage from key switch to solinoid to starter.All voltage was good to starter so I got a knew one.In the prosses I found out that the yellow wire coming from the key switch was bad ,its the small hot wire going to solinoid.Its at the internal wiring ,the plug that comes out off engine is broke,and there is another end broke also on the internal harness.I have a knew one on the way.I will include a picture.With that out the way for now i ran a 14 gade wire to it.With the knew starter it jumped up but wouldnt turn the flywheel.So I did some reading.It ended up being rust in the cylyinder walls.I sprayed down with pb blaster and let set a couple days.It freed up some.Then someone told me to put trasmision fluid in and let sit.I did and it freed up good ,it turns and starts right up.Know ive done some reading on why its not going fast .This is what ive done from my home work so fare. Ive flushed and changed lower unit oil,tested spark on all 4 cylenders and its good,tested copression with 1 at 60 psi,2 at 120psi,3 at 120psi,4 at 120 psi.When I run the motor water spits out under the flywheel kind of like a water pump in a car.It never did this before I cleand the cylinder walls.Its hard to see where its coming from because the water is spitting in my face.I hoping its a seel.If I have to take the flywheel of can you please tell me how to.I took the top bolt out but stuck from there.I havent done the full check yet to see if all cylenders are getting full.For now i worried about the psi in cylender 1.and the water coing fro under the flywheel.Im including pics of the internail wire harness and dont know what the broken end goes to.there are two broke i now the solinoid one.ty all

 

[Chinewalker]

Re: did as uch reading as i could but stuck.1966 500 thunderbolt

With one cylinder at 60PSI your motor needs to be rebuilt. Chances are your season of dealing with the 10mph thing might have killed it, particularly if the carbs are fouled. No fuel means no lube, which means it can kill the motor by running it like that.

That said, your water issue is probably an exhaust cover gasket - which could also explain why your motor rusted up the cylinder walls, which could also be the cause of your low compression issue. Water should NOT be coming out from under the flywheel - no way water can get under there - unless the block is cracked, in which case you've got even more issues.

Your wiring harness - least of your worries right now. I'd start by pulling the intake port covers off and inspecting the pistons. I'm betting you've got stuck rings (at minimum) and possibly a scored piston. If the piston is scored then you're looking at a rebuild or setting it aside and finding another motor...

 

[tkq23111]

Re: did as uch reading as i could but stuck.1966 500 thunderbolt

just took plug 1 out and water is coming out cylender.where do i go fro here.ty

 

[Chinewalker]

Re: did as uch reading as i could but stuck.1966 500 thunderbolt

It sounds to me like you've either got a bad gasket leak on the exhaust side or a cracked block. Those are the only ways water can get in there in any volume... Time to start taking things apart.

 

[tkq23111]

Re: did as uch reading as i could but stuck.1966 500 thunderbolt

ty. could you tell e the location of the gasket id ge going for.I going to try,if its a gasket id be able to fix hopfully lol.thank you.included is what ill look at for refrance.http://www.crowleymarine.com/mercury-outboard/395.cfm im thinking topic ,CYLINDER BLOCK AND CRANKCASE ASSEMBLY itea 46.what do you suggest.

 

[Chinewalker]

Re: did as uch reading as i could but stuck.1966 500 thunderbolt

Fixing the gasket won't fix the low compression. Time to get a service manual and start tearing the motor down. With the amount of water you had, combined with the fact that the motor seized at some point, probably due to water intrusion, means you have several issues going on inside and they need to be dealt with. Before spending money on gaskets or seals you need to determine if the motor is worth spending anything on and that will mean tearing it apart. If you find the block is scored and/or cracked, then it is probably time to set it aside and find something else. In other words, the water leak may be the cause of the problem, but it is not THE problem... Fixing it won't fix the motor...

 

[Chinewalker]

Re: did as uch reading as i could but stuck.1966 500 thunderbolt

ty. could you tell e the location of the gasket id ge going for.I going to try,if its a gasket id be able to fix hopfully lol.thank you.included is what ill look at for refrance.http://www.crowleymarine.com/mercury-outboard/395.cfm im thinking topic ,CYLINDER BLOCK AND CRANKCASE ASSEMBLY itea 46.what do you suggest.

To answer your question, the gaskets that I think are leaking are #40 and #38 in the cylinder block and crankcase section. You need to remove the water jacket cover, #41 to get to them and see what's going on. That might be the best thing to start with as you'd be able to see the pistons, too, and get a better idea of how much damage you might have. If this is a saltwater motor, it's also possible it has corroded through the block somewhere... Be prepared for broken bolts in either case - they're notorious for water jacket cover bolts breaking...