MACDAD260

While pulling the stock Thunderbolt IV distributor today from my 7.4L to swap it over to the 502 I found it to have almost 1/8" play in the shaft at the gear. I couldn't believe it because the last time I had the boat out in the fall it ran perfect! It has 508 hours on it. Is this unusual wear or is it normal? Is it possible to get a new shaft and bushing and rebuild this thing or do I have to go new? I would like to just repair the stock one as it should be a lot cheaper than a new one. If I go new what is the best aftermarket distributor and would I need a complete ignition system as well. Thanks.

David Stotz

I've had the same problem. Motor ran fine but had the same play in the dist. I've been told by two sources that the bronze bushing the shaft rides in is not available as a seperate part from Merc. I bought a new Merc dist. $234.00!

dyno

MackDad you allready sprung for the 502 dont scimp on the ignition....go with an Msd or Crane with a billet distributer you wont be sorry...my.02

Crazyhorse

I'm with Dyno on this one. The Crane Hi-6 is supposed to be a great setup too.

MACDAD260

Thanks guys, I was afraid you were going to tell me I was SOL. I think I will try to get this one repaired first before I spring for a new one. I'll give Floyd's Electric a call on Monday and see if they can do it. From what I have heard they might be able to. I'll let you know. See ya.

Mate 229

If you but a new billet unit go Mallory not MSD. The Mallory is a real marine distributor and won't corrode. I had a MSD and had to clean the cap after every run. The Mallory will also run without the control box which can save you a tow if it craps out.

Griff

Had the same problem with my TB IV distributor. The brass bushing was gone on one side and the shaft was grooved. Figured I was going to put on a new cap and rotor anyway, so just got a whole new TB IV distributor including cap and rotor from Bam Marine for about $200.

MACDAD260

Just an update on how this turned out. I found a local guy who rebuilds distributors. He had to special order a bushing, (odd size O.D) polished up the shaft and reamed the bushing to fit. He also drilled a .060 hole through the housing and bushing betwen the lower two rings on the housing for pressure fed oiling of the bushing. Cost me $35 bucks. Seems good as new.

Cignificant

In case anyone reads this thread and is interested, I have two used Merc distributors for sale $75/ea from a 1990 Cig. I also have two new (Still in the boxes) Mallory billet marine distributors for sale. They cost @ $300/ea, will sell for $225/ea.

(sorry for the blatant advertisement - I'm trying to clean out the garage)

[email protected]

BGIII

MACDAD, who did this for you? I need to have the same thing done A.S.A.P. Thanks