Cracked cylinder walls!

[the beave]

Will an outboard run with both cylinders cracked? I have a 1982 Mariner 25hp that was given to me. At the time it had a cracked water jacket that I repaired and then had to replace the water pump and impeller! Finally got it running this weekend and on the muffs it runs great but when it is immersed in water it runs but really lacks power! I pulled the plugs and both cylinders have water in them! I am wondering if when the water jacket cracked ( which I assume was water inside that froze!) could both cylinder walls have cracked and if so would it still run? I know that it could also be the water jacket gasket or the exhaust gasket (which looks like there might have been some leakage around it as it looks like there might be some rusty crud around it but no sign of water that I can see) I haven't been able to do a compression test yet as I don't have a tester but am gonna try to get one!

 

[latin monkey]

Re: Cracked cylinder walls!

take the powerhead off and install new exhaust plate gasket and also change the crankshaft seals in the upper and lower endcaps while you have it off

 

[the beave]

Re: Cracked cylinder walls!

Ok from what I can find there is an exhaust cover gasket on the side of the motor and an exhaust manifold gasket, both of which are obsolete! Which one would you mean and if they are not available, what can I use? Thanks

 

[the beave]

Re: Cracked cylinder walls!

Any other ideas?

 

[Faztbullet]

Re: Cracked cylinder walls!

You can order them thru iBoats as they are offered aftermarket thru Sierra if your is the American 25XD. The inner plate is 18-2717 and outer is 18-2716 and the powerhead base is 18-0336. If you have the Yamaha import order them thru a Yamaha dealer..

 

[CharlieB]

Re: Cracked cylinder walls!

Very first thing is to have your serial # at hand then go here

http://www.mercruiserparts.com/SelectProductLine.asp

Follow the links to get the parts view, parts # and availability of the part. If indeed the part is No Longer Available from your dealer, then take the part # and start checking aftermarket sources.

If all that fails then look up Sea-Way Marine in Seattle, they have a web site or call them, many times they have saved a motor by having a discontinued part on the shelf.

 

[the beave]

Re: Cracked cylinder walls!

Ok so mine is the Yamaha bulit one and I am unable to find any parts older than an 84 for them! As far as under Mercury goes, the exhaust side plate ones and the exhaust one are NLA! Is there any way to make these gaskets if need be? Will a compression test tell me what is going on or will I need to pull it apart to figure it our?
Thanks

 

[the beave]

Re: Cracked cylinder walls!

I have been able to locate all of the gaskets in a complete package so I might be ok yet! I finally got to do the compression test today as we had Hurricane Earl here yesterday! I did each cylinder a few times and this is what I got: the top cylinder had 100psi each time, the bottom one had 180, 170, 150, 140 and 140!
Any ideas?