76 115 mercury dies

[fishhunter2]

Hi, this is my first post, and I'm at my wits end with this engine!!. the engine will run perfect for two or three times out, then all of a sudden the engine just stops as if you turned off the switch, then after several starts it will start again, and may or may not do it again. I have changed cd unit twice and new coil, repaced wiring to cd unit, cleaned contacts in engine to boat harness, and installed an electric fuel pump. The only thing left is the distributor... anybody out there had this problem? or any suggestions......thanks fishhunter2

 

[Chris1956]

Re: 76 115 mercury dies

If you are sure the boat and motor harnesses are good, and the switchbox is getting good voltage on the red and white switchbox wires (starboard side), thn the dist. trigger may be intermittent.

Clean/Check the trigger connnections to the distributor. If they are OK, don't fret, the trigger will likely completely fail pretty soon.

 

[dutchdog]

Re: 76 115 mercury dies

I had my boat do that and it was the neutral saftety switch wires were loose. Just about pulled my hair out trying to find the problem.

 

[fishhunter2]

Re: 76 115 mercury dies

If you are sure the boat and motor harnesses are good, and the switchbox is getting good voltage on the red and white switchbox wires (starboard side), thn the dist. trigger may be intermittent.

Clean/Check the trigger connnections to the distributor. If they are OK, don't fret, the trigger will likely completely fail pretty soon.

thanks chris1956, I'm going to check a couple more things, then it's into the distributor. parts for this old of an engine are hard to find.. wonder if there are after market parts for the distributor........ thanks fishhunter2

 

[fishhunter2]

Re: 76 115 mercury dies

I had my boat do that and it was the neutral saftety switch wires were loose. Just about pulled my hair out trying to find the problem.

thanks dutchdog-- had already checked that out when relaced wiring..fishhunter2

 

[Chris1956]

Re: 76 115 mercury dies

There are aftermarket parts for the distributor. They are expensive though. The rotor is non-removeable and fragile, so treat it like glass.

 

[fishhunter2]

Re: 76 115 mercury dies

chris1956... thanks, I did find an aftermarket part and you are right, they are expensive. My neighbor told me when I first bought the boat that they are money pits, I'm begining to believe it after replacing the wiring, transom, floorboards, carpeting, and seems like about 500 rivets plus 2 cdi units and coil. I guess I can't quit now.......

 

[kenworth747]

Re: 76 115 mercury dies

Did you check to see if you had spark at the plugs first before replacing anything, And check fuel filters and check tank for foriegn objects, I went thru that same problem and replaced a mess load of stuff and found out my doughter thru a candy rapper in the tank when i was filling it, so the rapper kept blocking the screen.
Im sure you checked them , but just in case.

 

[donzi gt230]

Re: 76 115 mercury dies

Neutral safety sw. won't turn off a motor. Does it have a safety cut off switch-the lanyard thing? If so it may have a problem causing the shut down. Tho ignition parts could act like you're describing, I'd make sure to rule out other things first.

 

[donzi gt230]

Re: 76 115 mercury dies

BTW-since it wasn't the fuel pump, remove it for safety's sake.

 

[fishhunter2]

Re: 76 115 mercury dies

does anyone know if there are any resistance checks I can make on the distributator coils ( the three wire coming out ) it appears that I have voltage coming in but not sure if both coils are okay......... fishhunter2

 

[Chris1956]

Re: 76 115 mercury dies

There is a CDI test for all but the distributor. It assumes your coil is good, as most are. if the test passes, it suggests the dist. trigger is bad. You will find the test on this forum, and on the CDI Electronics.com web site.

 

[ufm82]

Re: 76 115 mercury dies

Electrical issues on old outboards = EVIL!!! LOL I hate tracking electrical issues. Just wanted to say that...

UFM82

 

[fishhunter2]

Re: 76 115 mercury dies

The problem solved, replaced distributor, also found charge voltage goes above 15volts when running with fully charged battery, and as I understand it anything above 14 volts can take out the distributor trigger circuits I built a simple zener diode regulator for white circuit from ign. switch to the CDI which holds voltage to max of 12.7 volts. I havent taken out to lake yet .. but have run for extented periods of time without even a miss Yea!!
Thanks to you guys for all the information..... fishhunter2

 

[fishhunter2]

Re: 76 115 mercury dies

There is a CDI test for all but the distributor. It assumes your coil is good, as most are. if the test passes, it suggests the dist. trigger is bad. You will find the test on this forum, and on the CDI Electronics.com web site.

thanks... fishhunter2

 

[Chris1956]

Re: 76 115 mercury dies

Fish, Those motors were made to have that unregulated charging system. It would be surprizing if it was sufficient to hurt the ign system.

That Zener Diode idea is a good one. I did the same on a motorcycle that was overcharging.