69 merc 800 ignition maintenance

[jake505]

Hi does anyone know how long the cap and rotor should last on one of these motors with the thunderbolt ignition. Are they just like a cars where you should change it when you do a tune up or do they last a lot longer. At $270 for the rotor and $177 for the cap I am thinking that these should last maybe just a little bit longer plus it doesn't look like a really easy job when the distributer shaft and the rotor are one peice.

 

[Faztbullet]

Re: 69 merc 800 ignition maintenance

I have never seen a cap or rotor that needed to be replaced from normal wear, the carbon brush and spring is usually worn/broken if engine has lot of time or set up. Part #393-1293A1

 

[Fuzzytbay]

Re: 69 merc 800 ignition maintenance

If they aint broke, don't fix em. Check the springs, brush's and button in the cap, thats all.

 

[jake505]

Re: 69 merc 800 ignition maintenance

thanks guys I kinda figured that was the case I was just wondering because I was going to do a full tune up figuring that it was like a car engine till I saw those prices. I hadn't run it for about 6 months because had to get some new controls and replace the impeller and just didn't have the time or cash so when I finally did get it fixed and started it was running a little rough but i think it was just old gas and it needed to be run wot for a little while. took it out the other day and ran great and when I was flushing it after I noticed it was idling a lot better. so I guess these parts do last a while considering these are the originals

 

[Gomer50]

Re: 69 merc 800 ignition maintenance

I think thats kinda funny I bought 1972 mercury 800 thunderbolt and thought I would do a tune up also.Figured new cap and rotor and points.I soon learned this is not the same as my truck.I have yet to see a distributor cap and rotor cost more than $50.00.When I called the local Marine shop for a Price quote and told me cap and rotorshaft for around 400 some Dollars.I thought he was kidding but he wasnt.So I will keep the old one because it does work fine..I had no Idea boat Motor parts were that expensive.I guess I need a second job now if I want to boat..LOL