1988/83 Mercury 115 6 Cyl Technical questions

[backmarker]

Good Day, my brother (mainly) and I have restored a 1966 Boat Locker "Malibu" The boat originally had a 1965 Mercury 1000 6 Cyl. Unfortunately we could not save the powerhead.

We opted to get an 80s model 6cyl with PTT, and the newer ignition system, in order to make it a bit more practical to use. After a year we managed to build a inline 6 with the 88 lower unit, PTT and gearbox, and an 83 Powerhead.

I have experience with OMC and the Japanese brands, but 0 on Mercury and even less on inline 6s​

here is a pic, 66 decals on, contemplating if we must do the 66 engine covers and crome beadings..





Issue 1:

Cooling system
Engine running water is coming out of pee-hole AND a tube on the water jacket between the spark plugs

 

[racerone]

Issue 1---The tube on the water jacket would be for a water pressure gauge.------You can just put a pipe plug in there like when it left the factory.---Issue 2 -----Other than just guessing and replacing parts what other trouble shooting was done ?

 

[backmarker]

Issue 1---The tube on the water jacket would be for a water pressure gauge.------You can just put a pipe plug in there like when it left the factory.---Issue 2 -----Other than just guessing and replacing parts what other trouble shooting was done ?

Checked for Spark on all cylinders, that's it...

 

[racerone]

Compression test done ?----Replaced fuel pump diaphragm ?--------Tried adjusting the low speed mixture screws.

 

[jimmbo]

On some of the older inlines that fitting was where the tel-tale was connected. The fitting looks like the right size for that, the fitting for the water pressure gauge was bit different