1975 Mercruiser - Condenser

[JasonM]

I have a 1975 Mercruiser 140 with a mallory distributor. The engine has been completely redone. The problem I am having is the boat will run great for about an hour and then it starts to bog out and then it stops running. We found that the boat keeps blowing condensers. When we replace the condenser it will start right up and we are good to go for another hour. When we opened the distributor to replace the condenser we noticed metal type shavings/pieces. Also the distributor was really hot to the touch? What would cause the condenser to keep blowing out? I was going to replace the distributor to see if that helps. Any advice would be greatly appreciated.

 

[Haut Medoc]

Re: 1975 Mercruiser - Condenser

Welcome to iboats Are you using the original coil or did you replace it?.....JK

 

[JasonM]

Re: 1975 Mercruiser - Condenser

The coil has been replaced....

 

[Haut Medoc]

Re: 1975 Mercruiser - Condenser

With the right one?....JK

 

[JasonM]

Re: 1975 Mercruiser - Condenser

I took the old coil that was on the boat to the parts store and they gave me what they say is the correct one. Looks like the same one.. I am a little concerned now. Can you shed some light on what the correct one should be??

 

[Haut Medoc]

Re: 1975 Mercruiser - Condenser

I don't have specific info on your new coil type, there are many different kinds.....It seems like you are getting too much juice to the coil, and it is frying the condenser......Get the #'s off the old coil for comparison......Better yet, call a mercruiser dealer for the part #. If you went ot Dougrussell.com or Bammarine.com you could probably find it there.....Are you sure that the + side of the coil is wired correctly? There is a resistor wire that runs the coil in the 'run' position on the key, and another one from the starter that provides extra voltage with the key in the 'start' position. If you are sure the coil is right, Merc. manual #2 says Prestolite #32193....If you do have the right coil I would look at the resistor wire.....Look in the "search" function, there are tons of useful posts on the subject...JK

 

[Dunaruna]

Re: 1975 Mercruiser - Condenser

Originally posted by JasonM:<br /> When we opened the distributor to replace the condenser we noticed metal type shavings/pieces.

Apart from the condenser/voltage issue, you need to remove the distributor and investigate.<br /><br />Aldo

 

[JasonM]

Re: 1975 Mercruiser - Condenser

What is the wire that goes from the negative of the coil to the side of the distributor? Does it need a resistor?

 

[Haut Medoc]

Re: 1975 Mercruiser - Condenser

The brown one? Ground ......And the other one should go to the shift interrupter switch.....JK

 

[Haut Medoc]

Re: 1975 Mercruiser - Condenser

Oh, and no resistor there, the white one (+)is the resistor.....JK

 

[JasonM]

Re: 1975 Mercruiser - Condenser

I am going to check the coil and then I am going to open up the distributor. I will probably need more help down the line. Thanks for your input

 

[JasonM]

Re: 1975 Mercruiser - Condenser

Well I bought a new distributor and when I took the old one off and turned it upside down the guts of the distributor were falling out. There was a bunch of plastic and metal fragments as well as a spring. I put the new distributor on and the boat ran like a champ. <br /><br />The boat has a new engine and the only problem now is that it will not go above 4800 rpm's. At the beginning of the day we could only get it up to 4200 rpm's but by the end of the weekend it was up to 4800 rpms before it would bog down. I talked to my father in law who I bought the boat from and he said that it is because we havent really broken in the engine yet. Any thoughts?

 

[Bt Doctur]

Re: 1975 Mercruiser - Condenser

If you have "resistance wire" in the circuit, coil says "use with external resistor". using a standard coil here will reduce the voltage going to the coil because the coil has a resistor built in. Plus there is an "electronic ign. coil" specific to breakerless systems.

 

[JasonM]

Re: 1975 Mercruiser - Condenser

Yes I have do have a wire and the coil does say "use with external resistor". Any other thoughts on why it wont go past 4800 rpm's.

 

[Haut Medoc]

Re: 1975 Mercruiser - Condenser

Jason, glad you figured it out.....A 140 is only supposed to get 4200-4600 R.P.M. @ W.O.T., if you have the right prop. You will kill your engine by running at those #'s.....4800 is too much already.....JK