Mercruiser Mag Mpi Horizon W/Bravo3

NickCruz

I'm still working on engine and outdrive. Can anyone tell me, If you have this motor, what your WOT RPM is and With what pitch prop?  Mine is only getting 4200 RPM with a 24 Pitch prop.  But I am getting 41+ MPH out of it. Just wondering what everyone else is running.  The book says 4700 - 5000.

Liberty44140

My 06 342 with the same engine and drive got 41 mph at 4800 rpm. Drives trimmed up, flat day. 22p 3 blade dual props. 

YYZRC

Right around 40mph at 5000 +/- rpm with Hill Marine 20p.  Same results with the OEM Bravo Three 22p (but took a lot longer to get there!).

reneechris14

My 05 was 40@5000rpm
350 mag B3 2.2 drive and stock 22 pitch prop

Aqua_Aura

Sounds like the 24 props are just a little "big" so therefore that is the resulting RPM. 

NickCruz

Any opinions or knowledge if running this prop 24P will cause long term damage to the engine.

NickCruz

By the way thank you all for your help it answers a lot.

trip_n

06-270
496/bravo3
4700 ish
24p
42-45mph

what kind of load
hows your bottom

NickCruz

Bottom clean no paint, 25 gal fuel 2 people 500 lbs, no water still testing boat.  I just had it out again and now spitting and sputtering to get to full power.  I ordered new Dist. cap and rotor and decided to put new wires also.. Maybe part to do with all issues.  Will let everyone know the results. 

aero3113

Replace fuel filters also.

NickCruz

First thing I did was have gas tank sucked dry, then added fresh non-ethanol fuel.  Then before running I changed all fuel filters.  Also changed Plugs and cap and rotor but wasn't sure if I had the correct ones so I ordered from Merc. and doing wires also then I will see how it runs before spending crazy money on props.
 

trip_n

also use gps
tap speedo

Liberty44140

Sounds like your concern is rpm and not speed. Your gauges may be off. Mine were always 200rpm lower than reality. You could be 600 off. I would confirm that and if 4200 is right, buy some 22p props that are for sale on this site

NickCruz

I believe my RPMs are off because at 4200 I was doing 42 MPH on GPS. Will check that.
UPDATE: I just came in from installing new wires and found #5 cylinder wire was off. So that should account for the spitting and sputtering.  

skuter99

On my 270 with mag350 mpi bravo 3 the analogue tach is 300 rpm higher than actual digital reading.

NickCruz

Mine does not have a digital reading, so I will have to get a tach to check it with.  I did notice that I would reach 4200 then I would have about another 1/4 throttle left with nothing happening during the push to full throttle.

NickCruz

Can anyone tell me what the fuel pressure should be with Just the key on, engine not running?  I found where the fuel pressure should be 43 lb with engine at 1800 rpm.

Pat310

Sounds to me like you may be running in guardian mode since rpms top out at 3/4 throttle travel. Maybe someone disconnected warning buzzer??  Would invest in vessel view mobile if you have smart craft compatible engine. Will give digital tach and any error codes that could cause you to run in guardian mode

Grahamu

I've just got vessel view mobile because the analogue Tachs are not accurate and I want to make sure the engines are synced when  cruising also fuel consumption at various RPM. Mercury engines in 2003 became smart craft compatible. If yours are later should be OK, with serial # of engines I can search it.

Spyderweb

VVM well worth the expense.

NickCruz

Will look into it

NickCruz

I looked into it and got excited about it.  But then read into it and it says motors from 2004 I have a 2003

aero3113

NickCruz said:

I looked into it and got excited about it.  But then read into it and it says motors from 2004 I have a 2003

It really depends on your serial numbers, you might get lucky.

Grahamu

Here' a link for serial #s

https://www.mercruiserparts/vesselview-mobile

If you have 350 MPI serial # 0M300000 and above it is smartcraft enabled.
If you decide to go ahead you will need to decide where to mount the module as you will need other harnesses. I am putting mine behind the icemaker and needed 15' and 20' cables with a junction box. I can supply part #s. It can be put in the engine compartment but you will still need extra parts that do not come with the module.

NickCruz

I believe I'm OM600000 and above. So I should be good.  Where do I find the extra parts?

Pat310

I have it on my 2003 5.0s. Works great. I’ve heard some late 2002s even had it. Think that 04 date is more for outboards. Bought all my extra parts on eBay.

Grahamu

I'll take photos from Mercury Manual and hopefully post tomorrow with part #s so you can source on-line.

reneechris14

it will say smart craft on the flame arrestor cover and the purple plug back right corner

NickCruz

I went ahead and ordered one from Amazon will be here tomorrow. Looks like the exact engine I have @reneechris14.  I will check my engine tomorrow, I'm taking it for a run after putting tune up parts and going to check air conditioner.

trip_n

has to be smart craft
so
you hava 350mag ?
i think you should be turning a 22p

NickCruz

Yep @trip_n, 350 mag mpi Horizon.  I it is not smart craft then I'll just send it back. Also I checked and you are right I should be turning a 22P but boat came with 24P and seems to get the speed 41 mph at lower RPM 4200 .  Maybe with time I'll find a 22P at a reasonable price, but for now I'll stick with the 24P.  Another prop is more then I'm willing to spend right now.