97 Force 75

[fish4rob]

Quick question about a difficult problem. I went down river the other day and run across sand bar. Look back and seems to be peeing fine. About 2 minutes later, engine dies and steam is coming from hole. Engine is obviously hot. Get home, take head off, and everything looks normal. Flywheel rotates easily and pistons move in and out no problem. Take off head gasket and there is a hole in it between the lower 2 cylinders. I clean a lot of debris out of the jackets surrounding the pistons. I know I need to replace the head gasket, but I am wondering if this is the typical reaction from a blown head gasket, or is there something else that I should look for. I have not checked compression. Do I need to do it before or after I change the gasket? I have a buddy that will help me with all of this that is much more mechanically inclined, but I'm out of town for the holidays and the what if scenarios are killing me. Thanks in advance. Happy Holidays.

Rob

 

[roscoe]

Re: 97 Force 75

Blown head gasket, caused by an overheat situation, caused by .... ?

You probably sucked sand/mud up into the water jacket, and plugged it up.

I would remove thermostat and drop the lower unit. Then flush the system with a garden hose by forcing water into the thermostat housing, then up the water intake in the midsection, then repeat as needed.

You might want to take the time to replace the thermostat and water pump impeller, as long as you have it all opened up.

You can't check the compression now, unless you re-instal the old gasket and the head, just a waste of time.
Closely inspect the cylinder walls, pistons, and rings.
Install the new gasket.
Do a compression test after you get it running.


Keep us posted on your progress.

 

[fish4rob]

Re: 97 Force 75

Blown head gasket, caused by an overheat situation, caused by .... ?

You probably sucked sand/mud up into the water jacket, and plugged it up.

I would remove thermostat and drop the lower unit. Then flush the system with a garden hose by forcing water into the thermostat housing, then up the water intake in the midsection, then repeat as needed.

You might want to take the time to replace the thermostat and water pump impeller, as long as you have it all opened up.

You can't check the compression now, unless you re-instal the old gasket and the head, just a waste of time.
Closely inspect the cylinder walls, pistons, and rings.
Install the new gasket.
Do a compression test after you get it running.


Keep us posted on your progress.

 

[fish4rob]

Re: 97 Force 75

Sorry for previous, just trying to figure out the navigation of this site. Anyway, I did pull the lower unit and it was caked up big time with sand and such. Replaced impeller and cleaned out thouroughly. I am waiting for head gasket, but I could not find one locally. I hope the problem turns out to be this simple. I'll keep you posted and thank you very much for the response.

Rob

 

[Kajun37]

Re: 97 Force 75

fish4rob...i am going through the exact same problem as you....only thing i'd add is take out the thermostat housing so your water hose will fit all the way down in the hole. i was able to get stronger pressure on the back flush that way...might be different on the force though...

i also put back on my heads using the old gaskets to do the back flush.

check out my thread on the johnson forum...have a few pics of the ton of sand in my motor and what came out when i did a back flush tonight.

http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=28;gtid=1231934;gpid=1232784#gpid1232784

roscoe...it doesnt matter what brand motor i have...i still have bad luck lol....i just cant win lol

 

[fish4rob]

Re: 97 Force 75

Thanks for the pics. I need to back flush, but I did dig a bunch of gunk out. I also had a beach around the water pump. Hope everything works out for you.

Rob