Hi ! Upgraded to msd'S on 38kv scarab. Had thunder bolt 4's . With the stock dist. the motors reved to 5700. With same everything else except msd with 5800 rev limiters,rpm's dropped to around 5,000 rpm. Also installed the adapters to make tachs work. Boat has(2 ) 720 hp 572's. Does anyone know if the tachs ore off or if the problem lies in the ignition.
A 28 deg. stop was installed and weak adv springs were used. It is maxing out at 34-35 total advance at 3500 rpm. Initial base was set at 10 deg adv. I really am thinking about going back to the t-bolt setup. Although boat seems just as fast with the msd's. Thanks for any help in advance. I'm going out now for another test run. BBB

I am running a complete MSd set-up on my 540. I didn't need any tach adapter. I have not had any trouble with it at all. Maybe the tachs are off.. If you are down 700 rpm, you should notice a big loss of speed. Do you have an inductive tach you can put on an engine to compare?

Hi ! I'm going to check with an inductive tach but am not sure that will be 100 % accurate with the msd's Thanks, BBB

The tachs were probably off with your old ignition system. I had a similar result when switching from stock to MSD. Went from 5600 RPM to 5100 RPM but gained 1 MPH with the MSD as an end result.... Tachs were off.

Unless I'm missing something the timing math here doesn't add up.
The 28-degree bushing(red) and 10 degrees of initial would be 38 degrees and with the weak springs(both light silver) the timing should be all in by 2400.
Just my opinion but I'd run the black bushing, which I believe is 18 degrees, allowing 14-16 degrees of initial timing, to provide 32 to 34 degrees total advance.
I didn't need the tach adaptors when I switched from T-Bolt to MSD either.
Keep us posted on the progress.

Hi ! Thanks guys for all the input. I'm gonna get to the bottom of this one soon. Anyway Kurt from Konrad is going to be coming out tomorrow and we are going to get this boat setup and propped right. My buddy Teddy wisely cancelled out on this weekends poker run, until we are sure we have this boat totally ready. See you guys in August !!! Thanks again BBB

Hey, you be sure and tell Kurt that Crazyhorse said hello and that I still owe him a bunch of beers if he ever makes to west Michigan!

Talked to Kurt this morning he should have you dialed in. Mine planned out perfect in the rough waters of Lake Michigan last weekend and never missed a beat. Put in the spacers and turn the drives out.

Mark

Hi ! went for ride today with Kurt. He knows what he's talking about. He is getting us the 1" spacers , and that should fix it. Thanks to all BBB

If you want to spin to 5700 you probably want to go with a higher rev limit chip, they have been known to be off by a few hundred. Try putting in a 6000 rpm chip and see what happens.