I have a 1999 mercury hp 500 carb, she fires right up when cold, but then after running for 10-15 minutes dies and wont start. I am thinking ignition module ?
Is there a way to test before I go drop the cash, or any other thoughts ??

Thanks Rick

Post your engine serial # there is a reason for it. THX

Also you had a few good hits back in the day and a lot of women loved your hit super freak.

Yes, they liked to move to it !! lol

engine ser # OL415478

thanks !!!!

Wanted to make sure your engine serial # did not have the overspeed assembly for part of the ignition set up. Those darn things go out down the road like crazy. Anyways the last 1.5 or maybe 2 years of the HP 500 Carb app did not have it installed anymore.

You never know what year the engines are in boats anymore with swapped outs and repo's that had so many on the market and still do but not as much. I just looked at a 2001 boat / hull that had 1997 serial # HP 500 carb engines installed and owner wanted to agree me up and down that the motors were 2001. Merc Racing did not make HP 500 Carb engines in 2001 and finally had to show him the all Merc racing HP 500 carb engine serial runs matched to build years.

Anyways your deal possible what Merc calls a Ignition Module kit if I recall it is around 300 dollars

next - possible problem is what Merc calls a spark control module assembly that is NLA thru Merc.

Next - have you change the coil and the coil wire ? that is your cheapest test to do to see if that is it first especially if it is the orignal. There is tests that you can do for ignition trouble shooting to pinpoint the problem & part. I do not have the figures to type that much indepth out sorry. Maybe someone can post a link to it from Merc or out of the service manual. Also I sold all my HP 500 service manuals so I could not even make a copy for anyone.

Next and I doubt that the ignition sensor under the distributor cap is the problem child, But will add, I had a couple here and there do this as they had heavy corrosion on them and when they got hot caused a lot more resistance causing a NO spark condition.. Anyways another possibility and not that expensive to change anyways. The newer style sensor here is fully potted and not prone to the corrosion effects under the distibutor cap like the years past. Also if yours has never been changed out I would change it anyways regardless.

next if it is your Ignition module (kit) the $300 unit for the problem - you will need heat transfer compound and make sure you use the 2 spacers to mount it against the heat sink plate. Clean the heat sink plate spotless to on both sides as well.

heat and resistance and bad grounds and low battery voltage and loose connections (anyone one or all) are killers for ignition components. Will reduce longevity 4 sure.

Thanks BUP.
Ya, I put in a new coil and was hoping, didn't help !! So, I guess im going to try the ignition module and or the spark module, if the spark module is no longer available through mercury
where might I find one ?

Sorry , had to . lol

http://youtu.be/QYHxGBH6o4M

When it doesn't start, have you checked it for spark? Are you sure it's an ignition problem?
Eddie

My feeling is the ignition module kit and that's why I posted it first in the post above --Merc lists it as Ignition Module Kit part # 840130A4 retail for $ 304.73 so my guess was very close on the price.

The Spark control module assembly (aka) - Knock Module to, I would wait to see what happens with the Ign module kit first. The Spark Controle mod is a lot lessor of the problem. But if needed try googling part # - this Mercruiser 805443 or 805443T again it is NLA thru Merc. also thru Merc price is NLA

True 100 % also from post 7 as I thought you checked that already 4 sure to know about being a no spark issue , but I was guessing.

very funny with the hits - Damn bring back the 80's. I would do that all over again.

I'm Rick James Bit$h