Need Help. Is there a way to improve getting up on plane for the 40 Express Cruiser?

Jodijoe

I bought a 2010 40 Express with twin 496 Mag 8 L Bravo 3s with 160 hours on it. It is slow to get up on plane. I don't want it to struggle with more people and weight on board. Can I upgrade the props? To what pitch? Wider trim tabs? Fuel additives? Or is this just a design limitation?

Black_Diamond

Can you hit the WOT rpm for your engines?  That will tell you if you are over propped (too much pitch). 

Fuel additives will do nothing. 

Engine tune up might help. Esp cap/rotor as they can corrode. 

jhofmann

I'm not sure what is considered "slow to plane" but years ago we had a 39 ft Searay with twin 454 inboards that would plane off with 12 people aboard, and with your twin 496 with Bravo 3s you should plane off even better. Like Black Diamond said, make your hitting your wide open throttle rpms. If you can't hit the rpms, you may need to change props. Usually when you go with a lower pitch number, you get a better hole shot, and get on plane faster. Some members on here have had good results with aftermarket 4 blade props. I'm they will chime in.

aero3113

 Make sure you are using your trim tabs correctly also.

Jodijoe

aero3113 said:

 Make sure you are using your trim tabs correctly also.

How's that? work them in slowly during acceleration? Or full engagement from the start?

Jodijoe

Jodijoe said:

I bought a 2010 40 Express with twin 496 Mag 8 L Bravo 3s with 160 hours on it. It is slow to get up on plane. I don't want it to struggle with more people and weight on board. Can I upgrade the props? To what pitch? Wider trim tabs? Fuel additives? Or is this just a design limitation?

Black_Diamond said:

Can you hit the WOT rpm for your engines?  That will tell you if you are over propped (too much pitch). 

Fuel additives will do nothing. 

Engine tune up might help. Esp cap/rotor as they can corrode. 




How do i tell if I hit the WOT or it needs a tune up?

Jodijoe

How do i tell if I hit the WOT or it needs a tune up?

jhofmann

Full engagement from the start (tabs/bow down), trim all the way in. You should also search "Hill Marine Props" on this site to see what people have to say. Most have had a very positive expierence.

Jodijoe

What do you mean by "cap/rotor as they can corrode?" Sorry for the stupid questions but Ive never owned a boat this large.

Black_Diamond

The cap and rotor electrodes can corrode from the damp conditions in the engine room. Unless they were done recently, betting they are due. Pretty easy swap out. Just be super careful tightening the distributor cap down. 

As for the engine rpm: Mercury has a max (wide open throttle) rpm range for your specific engines. Take the boat out on a nice water day, get on plane/trimmed out. Go to 100% throttle. Your rpm’s should be in the Merc specified range. Too low means you are over propped. 

Definately start with the tune-up first!

Handymans342

Some people should not own a boat. lOLOLOLIKIK

Dream_Inn

Well, I have the same boat just with a bravo 2 drive, but I boat with someone else that has the same boat with the bravo 3.  Not really any issues planning, just make sure the put the trim all the way down when getting onto plane, then put it up once on plane.

Jodijoe

Thanks for the responses. The props are original so I assume Rinker chose the correct pitch. I use the trim and trim tabs. Maybe I'm just used to the speed of the runabout getting up on plane.

Dream_Inn

Probably, you are pushing 12 tons around, so it may take a little more

Jodijoe

I forgot to mention that the drives are I/Os, not inboards, and that we are in fresh water, not salt water which should plane faster due to being heavier. I haven't boated in salt water so not sure if the difference in buoyancy is perceptible.

LaRea

Is the bottom paint in good condition?  A heavy coat of moss will kill performance.  Reach under and see what you can scrape off with your fingernails.  

Also look at weight distribution.  Even on that big boat, balance matters.  For example, do you normally run with a big beer cooler in the transom locker?  Try temporarily moving it to the v-berth.  If it makes you plane faster, balance might be part of your problem.  

On my 370, adding another 40 pounds of chain to the anchor rode made a big difference (because it's so far forward).  

Dirtythirty

Speaking from the perspective of a 420.... I have two sets of trim tabs.  the "inside" set is stationary and have no controls. They are there to lengthen the hull of the boat. The outside set functions as any trim tabs do.   I have to run with my trim tabs in the fully down position at all speeds except no-wake speed as they keep the boat level in the water. Otherwise I'll be staring up at the sky.  I would stand no chance of achieving plane without my tabs all the way down.

Black_Diamond

@Dirtythirty: if you have I/O’s, the Hill Marine 4x4’s will solve that aft digging in situation. 

Cableguy Greg

Black_Diamond said:

@Dirtythirty: if you have I/O’s, the Hill Marine 4x4’s will solve that aft digging in situation. 

He has pod drives on his 420.

jhofmann

NICE!!