I still have water coming out my upper exhaust( just below the cowling)
after replacing the 2 exhaust cover gaskets. The only thng I didn't do was use the anticorrosion grease since I had some pretty bad areas of corrosion I had to use some gasket sealant/maker to fill in these areas. then I torqued each bolt to 250 in/lbs in sequence x2. The water pressure from the pee line increased dramatically but there is still water coming out the exhaust. Any Ideas what I did wrong or can do to fix this? I'm hoping to gat a few more years out of this motor.
If your talking about the two rectangle holes in the upper rear of your midsection just below the cover that hides the nuts and studs that hold your powerhead on well...that's normal. There should be a mist coming out of them.
Those are the ones, shows how much I know. Boy thats a relief I thought
I may have made a mistake in the reassembly. I haven't seen any other
mercury inlines running at the lake I go on so I had nothing to compare it to.
I'm using a clymer manual so I was unable to tell if this was normal since they
cover such a broad range of engines. Thanks for the fast reply.
Thats a relief Bryan was wondering what prop is working for you as (I have the '77 850 Thunderbolt 4cyl too) I have replaced my lower with a unit from a 100hp w/prop but it needs to be changed. What kind of speed are you getting with your vessel. Thanks
I'm running a 21p prop that looks like it's been cut down to about 12.8'' measured with a dial caliper, I don't know if the pitch has been altered.
The boat was running 37.5mph gps but this was with 30* timing which I
have decreased to 25-26* and now runs 36mph. My lower unit has 2.33
gears yours may be different in which case you'll need a lower pitch prop.
You can check by pulling your spark plugs, put the control in forward gear then line one of the blades of your prop with the trim tab mark that blade
with a marker then mark your flywheel and timing cover. Turn the flywheel
counting how many turns it takes to spin the prop one revolution exactly.
Your LU is probably has 2.0 gears in which case you would probably need a 17p or 19p prop.
Thats a relief Bryan was wondering what prop is working for you as (I have the '77 850 Thunderbolt 4cyl too) I have replaced my lower with a unit from a 100hp w/prop but it needs to be changed. What kind of speed are you getting with your vessel. Thanks
Hi,
The 85 had 2.3 to 1 gear ratio LU the 100 HP LU has a 2 to 1 gear ratio.
Because of the difference in ratios you will have a little less torque so you will probably need one size smaller prop than you used to used on the old unit.
Mercury 850 water coming out exhaust?
Linear Mode
