1966 merc 950

[Mortamie]

My brother and I just got done redoing some of the wiring in my boat. The problem we were trying to fix was the battery terminals getting to hot when I am cranking on the motor. Well we hooked up the muffs connected the battery and tried starting the motor which until this point would not idle or stay running longer than 5 mins.. The cables still got hot and battery juice died quickly. My brother thought it might be having to small a battery so he hooked jumpers from his van to my battery in boat waited a few mins and started the motor. My motor came to life and after a couple pumps of the choke stayed running for well over 30 mins before we shut it off... My question is why do my battery cables still get hot at the terminals? Any ideas could help.. Also can I replace just the battery cables in the wiring harness or do I have to replace the whole thing?

 

[Faztbullet]

Re: 1966 merc 950

Ohm the cables to check resistance as these are know to corrode internally....

 

[boobie]

Re: 1966 merc 950

A regular ohmmeter won't measure that resistance. The way to check the cable is with a voltage drop test.

 

[Mortamie]

Re: 1966 merc 950

What size battery do I need for the merc 950?

 

[Mortamie]

Re: 1966 merc 950

How do I replace just the battery cables? I don't have the money to buy a complete new wiring harness.... If you could explain how to replace just the battery cables I would appreciate it greatly..



Thanks,
Mort

 

[Mortamie]

Re: 1966 merc 950

So my brother and I checked all the wires on the external and internal wiring harness the ohms were good on them all.. We noticed that some of the insulation on wires inside the motor are wore off so we are going to fix them.. But in the mean time we still can't figure out why my battery cables are smoking and getting red hot.... Any ideas? I really need help on this one.... Oh and my brother checked battery cables when hooked up to battery and motor was running... They read 32 amps.. Don't know If this helps.

 

[GA_Boater]

Re: 1966 merc 950

So my brother and I checked all the wires on the external and internal wiring harness the ohms were good on them all.. We noticed that some of the insulation on wires inside the motor are wore off so we are going to fix them.. But in the mean time we still can't figure out why my battery cables are smoking and getting red hot.... Any ideas? I really need help on this one.... Oh and my brother checked battery cables when hooked up to battery and motor was running... They read 32 amps.. Don't know If this helps.

How did you measure 32 amps? That doesn't sound right. The stator only puts out 9 or 16 amps, if I remember right.

 

[Mortamie]

Re: 1966 merc 950

He used his meter and touched both pos and neg to see what it was reading.. He said they read 32 amps.... Ian dumb when it comes to electric but he is good at it.... Also when cranking on the motor is when the cables get hot... It takes a lot of cranking to get motor to turn over and my battery loses its full charge after about 15 mins of trying to crank motor over... My battery is a 12v 500 amp 75 amp/hr deep cycle Walmart special... If I hook jumpers to the battery before trying to start my motor turns beautifully but cables still heat.. But by doing this the motor will start in just a few mins of cranking.... This is all while motor is cold... When motor is warmed up it will start almost instantly.... *shrug*

 

[GA_Boater]

Re: 1966 merc 950

I don't think he measured 32 amps, it doesn't work that way. That's beside the point. What's wrong is cranking for 15 minutes. That's why the wires are getting hot. It's time to start checking why the motor isn't starting quickly. Start with the basics - compression, spark test and fuel.

 

[Mortamie]

Re: 1966 merc 950

These are good already checked.... But the cables get hot within the first 30 secs of trying to start.... That is what I am worried about... I understand cranking that long is bad but for the cables to get hot after trying to crank for so little time..

 

[Mortamie]

Re: 1966 merc 950

Also I am not sure if I am trying to star properly.... I hold the choke button down while cranking.. Is ther a proper procedure for starting.... First boat ever...

 

[GA_Boater]

Re: 1966 merc 950

If it's cold lift the warm-up lever to about straight up, turn the key to start and press and hold the choke button. On mine as soon as it putts, I release the choke button. When it's warm I just turn the key.

 

[Mortamie]

Re: 1966 merc 950

Hmmm that might be a bit of the problem on my starting... If the warm up lever isn't full open my motor won't start.. When it is running and idling good I move the warmup lever back to locking position and motor dies instantly.... Not sure if this is bad or not....

 

[GA_Boater]

Re: 1966 merc 950

Sometimes it's just a matter of figuring out the routine. I forgot about pumping the bulb until it gets hard, then go through the starting steps. I think the choke method I use is peculiar to my Merc.

Like I said earlier, do the basics before twisting adjustments. Have you changed the fuel pump(s) diaphragm(s)?

 

[Mortamie]

Re: 1966 merc 950

Ya I rebuilt both fuel pumps... I am going to try and start the motor again this morning.. See if I can get it to start faster this time... Also how do I bypass the silinoid ? Wanting to check and see if that will make a difference...

 

[GA_Boater]

Re: 1966 merc 950

Jumper cable. Battery + to the + stud on the starter.

 

[Mortamie]

Re: 1966 merc 950

Ok ty

 

[Mortamie]

Re: 1966 merc 950

Here is my motor it is running in a few of the pics

 

[Mortamie]

Re: 1966 merc 950

Another one

 

[Mortamie]

Re: 1966 merc 950

My motor was running on muffs and was loud as hell.. It also sounded a little rough... After about 20 to 25 mins it started to lose its idle and stopped..... Idk what is wrong.. Ideas?