I have 1998 carb 500 hps. Is there a way to disable the rev limiter on the stock Merc ignition to run the motor on a dyno temporarily??? Doesn't the rev limiter short the ignition to ground? Can you snip or remove a ground or something like that? Any expertise would be appreciated.

Tom

You have Thunderbolt 5 ignition.

The rev limiter is "built in" to the ignition module.

I'm pretty shure the limiter's setting is 5350 rpm.


I'd beg, borrow or rent a different ignition system to do the dyno pulls.


jt

Tom
When I did my dyno pull the revlimlter hit at 5450 rpm with the thunderbolt V on my 1998 HP 500. Are you close to running yours on the dyno with the new heads? I was considering replacing the ignition so I could turn a little more rpm, but I think I will try to work with the tb V for now. Jeff

Jeff I'm quite a ways away. The thrust bearing surfaces on the rear main bearing was torn up on the "dyno" motor so it needs main bearings. So might as well hone block and crank and install new rings while I'm at it. Also rod bores have gotten out of round and need to be resized and bored. One set of heads arrived already but am waiting on cam shafts/springs/keepers etc. Just trying to get a plan for the ignition system without Breaking Out Another Thousand (BOAT).

BTW the heads look great. The anodized coating looks good and there are neat AFR logos on one end of each head.

Tom