Master Fuse for 496 Mag?

[rdranman]

Cuising in Prince William Sound, AK comfortably at 22 knots, instantaneously we loss all electrical power to the engine (496 Mag HO), ignition and intruments. Checked all battery connections, every fuse or fuse link I could find, etc. Was just looking at a Bayliner manual and it mentions a master fuse on the engine. I saw a 50A fuse block on the engine, but it was not set. Of at least I'm assuming it wasn't. It has a small yellow push button that when you push it, a small yellow tab pops out. Of course, I pushed the tab back in. I assume this is like the GFI circuit breakers in kitchens, etc. with a test button? Or does it actually contain a fuse inside? Is this what they refer to as the master fuse? Thanks for you help.

 

[Don S]

Re: Master Fuse for 496 Mag?

Post a picture of the circuit breaker and post the serial number of your engine. Things do change from year to year.

 

[ENSIGN]

Re: Master Fuse for 496 Mag?

There referring to the fuse mounted on the starter,It's on the same terminal as the positive battery cable is bolted to.

 

[rdranman]

Re: Master Fuse for 496 Mag?

Don S and Ensign,
The Serial # for the motor is : 1G480976 - this is a Mercruiser CPO I had installed late last year. First time out this year because of other issues. Afraid I don't have a picture as the boat is 50 miles away parked above the harbor where I launch from. The circuit breaker looks like a small black box mounted on front top of the engine on the port side. I just took a look at the old engine (sitting in my garage) and it has a red button with a 50 stamped on it and the words "Circuit Breaker Press to Reset" stamped around it. If the same is true on this newer 496, guess a new question might be should I have not pushed the little yellow tab back in when I pushed the button and it popped out? Was I just turning the circuit back off after resetting it?

Also, Ensign, as far as I know, the postive cable from my battery runs direct to the starter. Never actually looked at the battery connection, just hand traced the postive cable down to approximately where the starter is and felt that the connection was tight. Are you saying there is a fuse actually mounted on the starter?

 

[ENSIGN]

Re: Master Fuse for 496 Mag?

Yes,there should be a 90amp square fuse bolted on the starter

 

[rdranman]

Re: Master Fuse for 496 Mag?

Ensign - OK... when I head back over to the boat I'll check it out... is this a circuit breaker or an actual fuse?

 

[ENSIGN]

Re: Master Fuse for 496 Mag?

It's a square fuse made by mercruser and cannot be reset.It will have a orange and a red wires connected to it.

 

[Don S]

Re: Master Fuse for 496 Mag?

 

[rdranman]

Re: Master Fuse for 496 Mag?

Don, thanks! A picture is worth a thousand words. The upper doesn't look the same, but the function should be... lever goes in to be operational.... must be the fuse on the starter since the one circuit breaker on top was not thrown (lever out). Looking at the fuse on the solenoid in your picture and looking at a West Marine catalogue, this looks like it is something like what they call an "ANL Ignition Protected Fuse" or other similar types are "AMI/MIDI" Fuses or "MEGA fuses". At West Marine, these are all manufactured by Blue Sea Systems. Hoping to pick one up before heading to the boat (50 mi) instead of heading to the boat and coming back then back to the boat to put it on (who'd have thought no marine parts store near the harbor).

 

[Fun Times]

Re: Master Fuse for 496 Mag?

So you're prepared, the 90 amp fuse part numbers are, OEM Mercruiser part number 88-79023A91, Sierra Part # 18-8220, Mallory Part # 9-15510.

http://www.iboats.com/Mercury-Marin...7736638--session_id.532984239--view_id.466780

You may want to call ahead to west marine to verify if they have them in stock.

 

[26aftcab454]

Re: Master Fuse for 496 Mag?

I had the same experiance Saturday night--just cruising along and motor died, dash gauges went nuts. The motor would spin but not fire-trim for the out drive no work. Got a tow to the ramp--and found the 20Amp circuit breaker had popped on the fuse box controling all my lights, stereo, buildge & bower.--Just pushed it in to reset and everything good. I had been running all accessories for hours and figure it was over loaded.

Cuising in Prince William Sound, AK comfortably at 22 knots, instantaneously we loss all electrical power to the engine (496 Mag HO), ignition and intruments. Checked all battery connections, every fuse or fuse link I could find, etc. Was just looking at a Bayliner manual and it mentions a master fuse on the engine. I saw a 50A fuse block on the engine, but it was not set. Of at least I'm assuming it wasn't. It has a small yellow push button that when you push it, a small yellow tab pops out. Of course, I pushed the tab back in. I assume this is like the GFI circuit breakers in kitchens, etc. with a test button? Or does it actually contain a fuse inside? Is this what they refer to as the master fuse? Thanks for you help.

 

[rdranman]

Re: Master Fuse for 496 Mag?

Well, turns out what happened to me was a 15 amp fuse had blown on the engine. There is a wire bundle on top of the engine that terminates in a hanging fuse block (the cap actually says ''FUSES" on it). I never would have guessed. A friend at work who had replaced his old 454 with the 496 had the same thing happen to him. That's how I found it. Still don't know what those fuses are for or why they sit there or what caused it to blow in the first place, but at least I know about them now and have plenty of spares.