Mag To Ho
 

HI back in 2002 i put a HO cam and ecu on my 2001 MAG.lately i read somewere that i habe to drill the hole in the throttle plate to make it bigger,anyone know the size of the hole i have to drill.thanks

1/4"

If it idles, leave it alone.

So did you see any speed gains after the upgrades were finalized ???

Did you end up needing to drill the hole?

http://www.offshoreonly.com/forums/g...onversion.html

I did drill the hole..

boat was a twin step 30'...best I was able to get before updates was 73.9 on gps after update first time out it hit 78.4 on gps,,but props would only spin 4800 rpm,once I had props reworked and was able to hit 4950 rpm I saw 80.2 on gps..

I'd say it was worth doing it then.:boat::) Thanks.

What would a hole in the throttle plate do at WOT except possibly disrupt air flow? It should only affect idle. If it idles fine, leave it alone.

yes it idle but the idle is not steady it is just like the IAC is always working to keep the idle steady, the trottle body whistle and stop whistle again and again......

496 HO uses more air at idle than a 496 MAG and opening the throttle plate by-pass hole larger to 1/4"-5/16" stops the idle air motor from working so hard to stabilize the idle and allows the idle air motor counts to return to zero which tends to stabilize the idle at a more constant rpm. Its also sometimes necessary to adjust the throttle stop screw and generally open the throttle blade so the TPS voltage is between .62 and .68 volts on the scan tool.

Best Regards,
Ray @ Raylar