Cold starting issue Mercury 1500

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Cold starting issue Mercury 1500

how I did my old 1500.
I used a T fitting between the fuel pump and carbs on the upper pump.
fed that to a jonnyrude enrichment valve, cause I had one.
I used the nipples from an old crossflow bypass covers, simply tap them out with a pin punch.
carefuly drill the correct sized hole in the top two carb flanges behind the throttle shutters and install the nipples.
move the existing choke power feed to the solinoid valve.
you will now have a pressure fed fuel primer system.
pump the carb primer,rasise the warmup lever push the choke and it will lght right up.
mine was a hard cold start isue that mysef and a few others, suspect the labyrinth seals on the reed blocks were worn.
after sitting a few weeks it was very hard to start cold, unless you sprayed wd-40 or about anything else into the carbs.
with wd-40 it would light right up.
that 1500 was still runinng a few years back and I did the modification about 1989.
the choke setup on the old inlines as iffy when it worked well.
 

PrinceValium

Chief Petty Officer
Joined
Jun 2, 2010
Messages
421
Re: Cold starting issue Mercury 1500

Well we are taking it to the lake tomorrow and we will see if it starts as easy as it did yesterday. Yesterday when I tried it started on the second key turn which is great as far as I am concerned!
 

PrinceValium

Chief Petty Officer
Joined
Jun 2, 2010
Messages
421
Re: Cold starting issue Mercury 1500

Inline 6's are hard to start cold but are nearly impossible to "flood". They need a lot of gas. You can get a motorcycle electric fuel pump to fit under the hood. They are small. I fed only the bottom carb with a small copper cap tube adapted to the 1/4 inch fuel line,(Like from a thermocouple) and ran it through the carb screen on the side the butterfly opens. The pump was fed from a T in the fuel line from the premix tank. Fast idle up, Push the button for the fuel pump 3 seconds, Hit the key. Starts right up when cold. I did use a squeeze ball at first but wanted to be able to start from the drivers seat without having to go back and squeeze the ball. Part lazy and part makes my wife more comfortable when I dont have to poke this, squeeze that, and say a prayer to start the old 1973 inline 1500. She doesn't understand keeping old motors running. Her idea is buy a brand new motor for $15,000.

Yeah I hear you there...I was at that point about a few weeks ago and finally got it running pretty good. I was ready to get rid of this motor. Glad I stuck to it aftter many manynnights of thinking about how to get it running right and refusing to let it get the best of me. Instead of getting another motor we replaced the all the ignition parts including distributor, coil, switchbox, rectifier with parts from a 1150 this mechanic had. The ignition system that was on it was aftermarket junk and not working.

I was hard pressed to spend more than $3000 for a motor on a 1983 boat.
 
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