1999 OptiMax 135 Problem-Help Please

[jackbrown]

Well I just bought a 2000 Nitro NX 750 with a 1999 Merc 135 optimax on it. I took it for a test drive with the guy I bought it from and everything worked perfect on the boat. We drove it for a good hour at all the RPM ranges. So I take it out for the first time myself and I get on the gas and all of the sudden everything quits. Come to find out it is one of the 20 amp fuses on the motor. It iwas the C fuse that controls the starter circuit. So I replace it and go on my way and get 10 yards and the fuse goes again. Except this time when I go to put a new one in it sparks and blows the fuse before I can even get the fuse in the receptor. Now if I wait a good 30 minutes and let everything cool down I can put the fuse in without it blowing. However the fuses still blow when I try to go fast? Any help is much appreciated. I plan on taking it to a dealer to have it checked out but thought maybe someone here may know.<br /><br />Thanks.<br /><br />Jack Brown

 

[jackbrown]

Re: 1999 OptiMax 135 Problem-Help Please

No clues?

 

[double08]

Re: 1999 OptiMax 135 Problem-Help Please

Check all your connections and also for any shorts from a bare wire. Also look at your key switch for any shorts or connections touching. Good luck. Larry

 

[ronmold]

Re: 1999 OptiMax 135 Problem-Help Please

Get a manual and find all the devices that fuse supplies. One by one remove them from the circuit to find the short. The heat problem makes it sound like a solid state blackbox problem $$$. Good luck!

 

[jackbrown]

Re: 1999 OptiMax 135 Problem-Help Please

Well I have the Mercury Manual but it doesn't have a wiring scheme. Where can I find that? I hope it is just a short, but it is just really weird that it was fine on Friday then I take it out Saturday and it is doing this.......The problem has to be on the circuit that fuse is on, so that helps narrow things down......<br /><br />-Jack

 

[jackbrown]

Re: 1999 OptiMax 135 Problem-Help Please

And what is a solid state blackbox?

 

[sledhead041]

Re: 1999 OptiMax 135 Problem-Help Please

First of all we need to get it down to what circuit we are talking about. There is no fuse in the starter circuit. There is a main power relay that supplies power to three of the four fuses. The four fused circuits are: The fuel pumps, Injectors, oil pump and CDM’s, and the trim. As far as being lettered I don’t remember, but if you look at the wires going to and from that fuse you can determine what circuit it is and then troubleshoot that one instead of all of them.

 

[jackbrown]

Re: 1999 OptiMax 135 Problem-Help Please

Well in my manual it states these exact words "Fuse C-Starting Circuit Fuse, 20 Amp" But that doesn't matter any more because I got it fixed. I found a wire that had some metal exposed. It was in a group of wires that was right next to my starter. So my guess is that when I had the motor running at idle it didnt shake the wire enough to hit the starter. but when I got on it the wire would probably hit it and short out. So I wrapped it in electrical tape and off I went. I hope that was the only problem. But it did run just fine yesterday......no blown fuses.<br /><br />-Jack