Ufoman420

So I just changed out my motor to the hp500 from the gen 6 454 carb motor. I took the boat out and im hitting a revlimiter right at 4800-4900 rpm. I did double check the tach with a timing light that has rpm and another rpm guage and it is right. I would like to change the rev limiter up to 5400 or so. Is there anyway to change the rev limiter on the stock ignition? any help would be great like part number and locaton of the limiter and how to change. I tried to do some research but came up with very limited info. thanks.

FIXX

iTrader: (2)

you need to find a hp module for the ignition...

Ufoman420

Ok it is just called merc hp module? Or is there a specific model name?

FIXX

iTrader: (2)

yes,,its a V8 HP,,thats if you have the thunderbolt IV..
http://www.ebay.com/itm/Mercury-Merc...s_Gear&vxp=mtr

timing curve chart for all the modules..
http://www.mtboats.com/mercuryigniti...cemodules.html

Griff

There is no rev limiter built into any TB IV modules. It is a separate box/component and was only used on blue Merc Racing engines.

If he has/had a rev limiter on a black Merc engine, then he has a TB V ignition.
I'm not 100% sure what he has, but I think it is this
http://www.mercruiserparts.com/Show_...CAL+COMPONENTS

If so he needs to replace part # 26 with one from an HP 500. In the long run, it would probably be less $$ to convert the entire thing to an MSD or TB IV with MSD.

Ufoman420

Thank you. It was a merc black engine 454 330hp was the original motor in it. I am still using the stock ignition system. From what I found out the ignition control box that has the revlimiter is under the mercathode. So all I need is that hp box and the rev limiter will go up to where it should be?

Ufoman420

I suppose i will look into a msd box that may make my life better and easier
thanks for your input everyone