98 Force 120hp head gasket

[bryan39]

I have a 98' Force 120hp OB 4cyl with water on the #1(top) sparkplug and motor was working 90% top end prior to finding water.
I have a manual and am going to change head gasket, thermostat, and thermostat gasket, hoping no cracked block. Wanting know of any unexpected steps in process.
Manual indicates remove thermostat, remove cylinder head bolts, remove gasket and its residue, use emory cloth, check for warpage, apply sealant and gasket, install/torque cylinder head bolts in order, and replace thermostat and gasket.
Are there any steps I should know about that above don?t cover?
Is my speedometer not working possibly related to same problem?, as pitot tube from motor to indicator already checked.
I appreciate any advice, Thanks

 

[pnwboat]

Re: 98 Force 120hp head gasket

It's pretty straight forward. Worse case scenario...you might have a frozen head bolt that may break when unbolting. Or I guess you could have a warped head. Both problems are not difficult to fix.

Use some anti-seize compound on the threads of the head bolts when you re-assemble. Use a torque wrench and tighten to 225 inch pounds, NOT foot pounds. Follow the tightening sequence in the manual.

Reminder per the manual. Undo the thermostat bolts before you take the head off. Sometimes they can be a problem. It's easier to torque down on them hard to loosen while the head is still bolted to the block.

The speedometer problem is not related to the head gasket. Most common problem is blocked tube from debris, pinched closed or a hole in it. If that checks out OK, then I'd start looking at the gauge itself.

 

[IMPATIENT 1]

Re: 98 Force 120hp head gasket

I have a 98' Force 120hp OB 4cyl with water on the #1(top) sparkplug and motor was working 90% top end prior to finding water.
I have a manual and am going to change head gasket, thermostat, and thermostat gasket, hoping no cracked block. Wanting know of any unexpected steps in process.
Manual indicates remove thermostat, remove cylinder head bolts, remove gasket and its residue, use emory cloth, check for warpage, apply sealant and gasket, install/torque cylinder head bolts in order, and replace thermostat and gasket.
Are there any steps I should know about that above don?t cover?
Is my speedometer not working possibly related to same problem?, as pitot tube from motor to indicator already checked.
I appreciate any advice, Thanks

your exhaust plate has a crack in it, been there on my 1998 120hp force recently pull the cover off the exhaust chest and look the plate over very well for a crack. what will happen is water enters the exhaust chest threw the crack , sprays towards the exhaust ports and gets sux'd into the cylinder and block. pm me if your plate is cracked, i've already found a good place to get em they have been redesiged as well.

 

[IMPATIENT 1]

Re: 98 Force 120hp head gasket

#33 in this link is the plate i'm talking about

http://www.crowleymarine.com/mercury_parts/2531/110.cfm

this is where i got mine:

http://boating.wholesalemarine.com/search?Screen=SRCH&w=8197791&x=23&y=11

i bought a engine master gasket set offa ebay so i'd have all the gaskets for the motor i'd ever need, so i had the gaskets on hand for the exhaust cover/plate.

 

[bryan39]

Re: 98 Force 120hp head gasket

Thanks, for the responces. Inpatient, exhaust plate culprit for water on #1 plug only?

 

[IMPATIENT 1]

Re: 98 Force 120hp head gasket

Thanks, for the responces. Inpatient, exhaust plate culprit for water on #1 plug only?

yes sir, i had a misfire that drove me nuts trying to find. well everytime i ran it, #1 would get wet and foul, all the plugs would show just a smidge of water, but #1 always showed it worse. i pulled the head off thinking the same as you, headgasket was perfect, couldn't figure out where the water was getting in at. i started researching old threads here and found someone that had issue with the plate, i went out and pulled it off, sure enough there it was staring me back in the face.it had a 2in split in the plate. very appearent how the water was getting in once i saw that.

i've been into dragboats all my life and just recently bought my 1st outboard boat, this 1998 120hp force on a 1998 maxum 18ft xr. happy with the boat, not so happy with my 1st outboard being a force. i've already replaced all the reeds, went thru the fuel pump, new coil on #1 cause the other was rusted, new plugs, new water pump kit, now i'm waiting on a flywheel and stator. i've only ran this thing on the lake for less than 2hrs

 

[bryan39]

Re: 98 Force 120hp head gasket

Received my Head gasket, got head off . found tear in gasket by #1 cylinder where had water on #1 sparkplug. New question. Ive seen lots of comments of not using Head gasket sealer . Manual indicates using 92-920113-2 sealer to cover side of Gasket. What do you all think? If so, does it need to be that specific sealer?

 

[pnwboat]

Re: 98 Force 120hp head gasket

Doesn't hurt but I'm not sure it's 100% necessary. I've replaced several head gaskets over the years on my 1988 Force 125 HP trying to fix compression/water leaks (Problem wasn't the head gasket after all). Sometimes I use the sealer and sometimes not. Either way, I've not had one leak. If you want to error on the side of caution, use it.

As far as the type of sealer, I've never used the type mentioned in the manual. I just used standard automotive type head gasket sealer. Maybe I'm just lucky, but that's been my experience.