Whats the scoop on pushing the timing up to get more hp out of engines?
I'm running a HP500, to get the most out of the engine should you run the timing at Mercury's recommendation or should you push it hire? The specs are for 14 deg BTDC. at idle. Is there a preferred rpm that you should set the engines timing up at?
Whats does a dyno tell you when it comes to timing.

The 20* of advance comes in gradually and is all in at 3000rpm.

We talking Carbed or EFI?

I used to run 36* total advance. Ran one on the dyno and pushed it to 38 degrees, it ran good but we backed it off to 36* when it was in the boat.

On the dyno less timing will make your exhaust temps go way up. Adding more timing makes the exhaust temp go down, makes more power but then you can get into detonation if you go to far.

I usually set timing at full advance 3000-3500 rpms.

Panther,

How much more HP with 36* vs 34* on the dyno and can you feel the difference in the boat between the two settings?

Mark

It's been a few years since the dyno pull but I think it was in the 10-15 hp range. When the timing was advanced the motor was happier and burned fuel better.

As far as seat of pants difference, you won't be able to feel it. One thing you may notice is the engine idles smoother and starts better.

After a good run the boat seems to take awhile to idle down.
Was thinking that maybe timing to high. Haven't stuck a timing light on it yet.
As for the engine it is carbed.

The 500EFI's run 36 degrees, Can't imagine pushing it much more than that on pump gas. A prior 502 mag with solid roller, dart intake, 1050 Dominator liked 36 degrees also.

I have HP500 carbs set at 37 degrees total advance - it makes a difference vs. 34 degrees. I always use either 92 or put a bottle of octane booster in - made about 2 mph difference on a 38 Fountain

LPboater,
Does your engines take awhile to idle down after you pound them a little bit? Or when you shut them down the engine seems to try to continue to run?