Maximum Rpms?

GK · 07-10-2006, 02:34 PM

Does anybody know what the maximum RPMs at full throttle a 1999 38' AVS with twin 502's (stock) should be running? I'm getting 4300 and was expecting closer to 5000. Thanks.

2 Trick Rick · 07-10-2006, 04:20 PM

4900/5100 Is what one at the marina is running, 4300 Seems way to low for 502ci engines.

BY U BOY · 07-10-2006, 04:36 PM

4800 /5150 I Would Not Go More Than 5200. What Props Are You Runnig.

satisfactionII · 07-10-2006, 04:56 PM

4900 to 5100 should be well within reach. How many hours on the engines? If you are around 300-375 hours consider haveing the heads reworked. You could have weak valve springs, causing your valves to float and thus you will loose RPM (according the machine shop). I have the same engine and after the new valve springs were installed I got back to 5100 easily. My old valve springs were so weak I could compress them by hand.

GK · 07-10-2006, 05:15 PM

Thanks, the engines have 500 hrs and I'm running a total stock factory Bravo one set up, nothing fancy in props. The interesting part is the top speed is very good at 72 knots of the GPS.

2 Trick Rick · 07-10-2006, 06:26 PM

Quote:

Originally Posted by GK

Thanks, the engines have 500 hrs and I'm running a total stock factory Bravo one set up, nothing fancy in props. The interesting part is the top speed is very good at 72 knots of the GPS.

72 Knots? That’s like 82/83mph! You best check your tachometers, Thay may be off

GK · 07-11-2006, 09:14 AM

I had the top end speed confirmed with a hand held GPS in addition to my dash mount still showed 72 knots trimmed out in perfect lake conditions. It just doesn't make sense with stock engines only running at 4300 RPM. I'm planning on sending the boat in for some engine mods at the end of the season and will get the tachs checked.

Thanks for all your feedback!

2 Trick Rick · 07-11-2006, 11:56 AM

Quote:

Originally Posted by GK

I had the top end speed confirmed with a hand held GPS in addition to my dash mount still showed 72 knots trimmed out in perfect lake conditions. It just doesn't make sense with stock engines only running at 4300 RPM. I'm planning on sending the boat in for some engine mods at the end of the season and will get the tachs checked.

Thanks for all your feedback!

What size props are you running?