RPM

planesailing

What sort of RPM should I get from my rinker 242 powered by a mercruiser 5.7efi and bravo 3 outdrive? Took it to sea for the first time yesterday and struggled to get above 3000 RPM until it got onto the plane and then managed to get about 3700 out of it. It did seem very sluggish getting onto the plane and I had to trim the leg quite a bit to get up onto plane. Is this normal?

Weber

I believe on that boat you should be around 5,000 at wot.

LaRea

Yes, that's definitely not right.  Does the hull have severe bottom fouling?  That could be holding you back.  If not, either you have the wrong propellers or your engine isn't producing full power.

planesailing

The boat has just been anti fouled and had a full service. The boat had been unused for about 2 years by the previous owner so yesterday was its first use in 2 years. Any ideas why it is not producing full power?

JC290

what pitch prop? what kind of load did you have in it? definitely something strange. i had a 242 with 5.0 and alpha drive never had a problem

planesailing

Not sure what pitch the props are. Went out with 2 adults and full fuel. Water tank was empty. Going to take it back out this afternoon on a longer run with same load and see if I can get anymore out of it.

JC290

Light load she should jump up. what kind of speed were you able to plane at? Trim tabs?

planesailing

Was getting into the plane at around 20 mph. The stern seemed to be sitting very low as I powered up to get it onto plane and had to trim the leg up quite a bit to get it on plane.

planesailing

Should the trim tabs be set bow up or bow down prior to getting on plane?

JC290

if you were trimming the "leg" I assume that is the drive on this side of the pond. so it should be fully down while trying to get on plane and than adjusted after you are on plane. That could be your whole problem. 

aero3113

I have a 242 with a carbed 5.7 (alpha 1) and it can be sluggish at times if you don't have the drive and trim tabs configured correctly. Make sure you have your drive all the way down and trim tabs all the way down before you try to take off. once you are up out of the hole bring your tabs back up then bring the drive up to its sweet spot. I cruise around 3200-3600 RPM. I think I get 4600 RPM at WOT.

Here is a link to some specs:

https://www.perfprotech.com/blog/tech-specs/mercruiser-v8-marine-engines-specifications

aero3113

here's another link:

http://www.sterndrives.com/merc/sternspecs.html

planesailing

Thanks aero. I'm not a million miles away from those figures then. I'll take it back out this afternoon and see how it performs today. What sort of RPM are you producing before planing? And yes we call the "drive" the "leg" over here! Ha

aero3113

I'll have try to look tonight. I think when I try to get out of the hole its at around 3000 RPM.

planesailing

Took it out today and it performed much better. Got onto the plane with ease and wot at close to 5000 RPM. Think trim tabs could have hampered performance yesterday and the fact that the boat hadn't been used in over 2 years. All is good now though! 

JC290

Glad to hear enjoy 

raybo3

Awesome enjoy it now