96 3200 SCR Performance Questions

[McGofy]

I just bought a real nice, fresh water, 96 3200 SCR. Twin 7.4 Carbuerated with Bravo 3 drives. I have read a BUNCH of great stuff already, awesome.

I do not know what props are on her yet, but she gets on plane reasonably, and cruises at about 30mph at about 3200 rpm. The challenge is that when best trimmed, I am only getting about 3800 rpm, about 35mph. I am thinking the props are too large.

What kind of performance do you think I should get?

Also, I took it on a sea trial everything is fine. after sitting for an hour, i went to start her up , and one of the horns stays on. The oil pressure gauge looks good, the temperature gauge looks good. The boat is basically cold,

Any ideas??

[mmwjr]

Welcome aboard.

The WOT should be 4600 - 4800 rpm. Try mercruisers prop calculator for suggest prop size.

The alarm will sound for one of three things; oil pressure, low gear lube, and engine temp. These use switches that close when their threshold has been met and are seperate from the sendors used for the helm gauges. I would start by checking the gear lube resevior level as this is the most common issue.

[McGofy]

Thanks Mike

Should the reservoir be low, can that be added to from the topside, or do you have to fill gear lube through the lower unit itself. (I recalling having to do that on my outboards by removing the lower and upper caps, and pumping the gear fluid in until it overflows)

[mmwjr]

The reservior is a clear plastic bottle on the engine and has a cap to fill it.

Note when changing the gear lube it needs to be filled by the drives bottom plug just like the OB to ensure no air is trapped in the drive.