78 mercury 900 distributor

[Glastron Fisher]

What distributors can I use for my 78 mercury 900 6 cyl, I've been searching all winter and the brand new trigger I need is 550 dollars, I'd like to buy one used but don't know what years or hp ratings I can use, I found a 75 85hp 4 cyl. Will this match up to mine if I use my cap?

 

[Faztbullet]

Re: 78 mercury 900 distributor

It will work all you need to do is change rotor disc internally......

 

[Glastron Fisher]

Re: 78 mercury 900 distributor

How difficult is that? I ordered a complete distributor for a 85hp 4 cyl for 200

 

[Glastron Fisher]

Re: 78 mercury 900 distributor

So I bought a 4 cyl distributor off eBay, what would happen if I install it as is with the 4 cyl rotor disc and my 6 cyl cap? It seems too hard to get the disc off

 

[DirtyOldBoat]

Re: 78 mercury 900 distributor

You'll ruin your motor if it runs at all.

 

[Faztbullet]

Re: 78 mercury 900 distributor

It seems too hard to get the disc off

Get a manual and disassemble the distributor and swap it. The rotor button does not come off so dont try to remove it or you will be looking for a shaft!!!!

 

[Glastron Fisher]

Re: 78 mercury 900 distributor

So how easy is it to disassemble? I've read about it in the manual like 12 times but not sure if it's something I'll be able to do, I work in an automotive shop and have good experience but being this small ad expensive it worrys me, and if my triggers bad I can switch just the rotor without the trigger? And do I need a press for any of it?

 

[buddhapi]

Re: 78 mercury 900 distributor

I too, own an auto repair shop, and knew nothing about these distributors until last summer. I worked on a 1150 that's been laying around over a decade, and the distributor was froze up tight. First, mark the flywheel and distributor gears before you remove the distributor. do not turn the motor over once the distributor is removed. with a lot penetrating lube, I got it all disassembled, cleaned corrosion off the shafts with some scotch brite, and reassembled. I now have a great screaming motor back on the lake again. find an exploded view of the distributor before you take it apart.

 

[DirtyOldBoat]

Re: 78 mercury 900 distributor

It's not that hard if you have a manual. You have to be *REALLY* careful of the sensor that reads the rotor disk...when you're tapping out the rotor, it is very easy to break it off with the disk, and ruin your trigger. Other than that, it should be pretty straight forward.

 

[Glastron Fisher]

Re: 78 mercury 900 distributor

Well I know someone with a boat repair shop so I'm going to see what deal he can give me on replacing it, I figure 5.50 for a new trigger and I'm 200 in so far so might be worth having a prop do it

 

[Glastron Fisher]

Re: 78 mercury 900 distributor

So I disassembled the distributor, for some reason my service manual from servicemanualvault.com did not have disassembly on my distributor, only assembly so I just messed with it untill I got it and when I put it back together I installed the shaft that was gr

 

[Glastron Fisher]

Re: 78 mercury 900 distributor

That was ground down and had to pull it apart again, now I can disassembly these things in minutes. Hopefully tonight I will get everything buttoned up and start it