1973 mercury 650 3 cyl thunderbolt

[nrosseau]

Awesome thanks merc850 did you happen to read my post above my motor seems to flood at low speeds is there a way to fix this?? I don't know much about the carbs I am more knowledgeable on the fuel injected ones

 

[merc850]

Set the low speed needles at 1 1/4 turns out then run motor in F gear in water and turn them slowly in then out until motor runs smoothly then give them 1/4 out; motor should accelerate smoothly and idle around 600 rpm, if it still runs poorly you might have to set the float levels. If you get an alt tach connect it to one of the Yellow wires on the rectifier not the Red one.

 

[nrosseau]

I am assuming that the brick with the two yellow wires is the rectifier. Which yellow wire does it matter? I don't feel like blowing my boat up today that is why I'm making sure it is indeed the rectifier. Thanks for all info that you guys have given
Also does the gauge of the wire matter I was thinking about using 12 gauge.
Oh one other thing my spark plugs are flat I was thinking about replacing do I need to get flat one the reason I ask is because they are pretty hard to find they are l20v. Also I don't think my battery charges when the motor is on could could I need a new rectifier.

 

[merc850]

Hook it to the top one 14 gage is ok and make sure it never touches any part of the block - and those connections are looking pretty corroded you should clean them especially the red one below the yellows, all the power connections should be rust free. Do all the work with the + battery cable disconnected. The spark plugs CHA827(L76V) are around $6.00 ea. and they are good for a few years that's why the call them Perma-Gap.

 

[nrosseau]

I never work with electric with the battery hooked up at all, it is my number one rule. Awesome 14 gauge is even better and thanks for the info on spark plugs and corrosion. now my question is how to keep the rust from coming back dielectric grease??

 

[merc850]

That gray stuff on the terminals is liquid electrical tape which will work or you can use Mercury's anti corrosion spray and grease - that's what I use. If you run in saltwater the spray can be used anywhere on the motor and the grease is good on propshafts, nuts and bolts.

 

[nrosseau]

Quick question I did a pressure test and I have a large leak under the water pump base it looks like the guy that did work on it before me tried to get the base out and possibly cracked it. What I need to know is how do you remove it. It is pretty stuck and some help would help a lot thanks I hope it is not a huge pain in the butt

 

[merc850]

Look for a FLUSH screw slightly below the top of the gear case this must be removed before prying the base out.
The PO sounds like he's a total butthead!

 

[nrosseau]

Thanks that worked and it was cracked like I figured. So I ordered a new one not bad 34 bucks so that pretty much covers the entire motor.