The distributor bushing I had replaced in my stock Merc distributor 90 hours ago is getting loose again. I think it is time for a new one. MSD has a new Marine Ready-to-Run Pro Billet unit that looks attractive. It does not need an ignition box. A buddy of mine just bought the auto version of it and I saw it today. Looks good. Are these things reliable? They seem to be fairly new so I wonder if anyone has experience with them. The other option I am looking at is the D.U.I. I have heard nothing but good things about them. They are both priced about the same when you consider that the D.U.I. unit includes a coil. Any opinions on what I should buy? I want to stay away from the standard marine MSD with an external box. My motor is a stock 502 mag.

I went with DUI, simple & reliable. You can buy the Rev limiter as well. If I was going spin my motor more than 5600rpm I would probably use the MSD. Mine was easy to install & set up. Power & tach wire only. I have not read or heard of anyone that has had problems, plus no coil to mount makes it even easier. Customer service was great.
John

Seems like MSD's are kinda hit and miss. Some people love them and some don't. As far as the D.U.I. systems all Ive heard is Good! Customer service is great. Dennis Moore really likes the DUI system. You can get parts for them ANYWHERE! Which makes it real nice. They CUSTOM build the advance for you also. Do a search on the board you will get the info you want.....
BH

Do a search in the tech section on DUI. Then go buy one.
Gary

I have ran a DUI (one in the Webbcraft, and 2 in the beak boat) for three seasons and report absolutely no problems. Davis family is very nice to deal with and will custom curve the advance for each application. Price is about half of what you would pay for a full blown MSD system.

When I purchased mine, they said they were trying to expand into the marine market more and were hoping word-of-mouth would work better than expensive advertisement, I think it has.

I also agree about MSD. I had a box go bad in between rounds in a NHRA Competition Eliminator race several years ago with no advance warning that cost me the race.

Just my .02

OR

I replaced me merc with a DUI and I am going on my 4th season with it. No problems and parts are everywhere.

In a 5000+/- rpm engine there is no advantage to MSD. Now comes their unreliability factor. I've seen too many first hand problems to put them in my boat , but then I have two TBIVs with almost 800 hours and they are fine.
Never heard anything bad about DUI. (unless of course you get caught on the highway ){that was bad}

3 and 4 seasons? I've got about 12 years on a pair. No problems.
Gary

That's great to hear, Gary. Good confidence builder.

OR

Hmmm. All good about the D.U.I. and so-so on the MSD. That is what I thought too, just wanted some more opinions. I like the D.U.I. because it is simple and GM HEI ignitions were always reliable. Now all I have to do is decide on a color!

Thanks,