Merc 75 4stroke converted to 90 or 115?

[Hot Runr Guy]

Originally Posted by Lunddude

What people don't understand is a 75, 90, & 115 are all the same motor just different ECM programing and a little restrictor ring in the 75 air box is all that seperates the 3 motors. Look up the specs on all 3 and you'll see they are the same.

Lunddude,
As long as Simon is "messing" with the mapping, have you asked if they can address the high-altitude issue? Sure would be sweet to get all 115 horses out of it, at 5000ft.

HRG

[jrdonicht]

Doesn't the Mercury 75,90,115 have totally different intake silencers not just a simple restrictor ring like Yamaha's have?

[Lunddude]

Originally Posted by jrdonicht

Doesn't the Mercury 75,90,115 have totally different intake silencers not just a simple restrictor ring like Yamaha's have?

Remove Part #10

http://www.marinepartsplus.com/catal...01362/12586-50

[jrdonicht]

Originally Posted by Lunddude

Remove Part #10

http://www.marinepartsplus.com/catal...01362/12586-50

I see the part but that part is only listed for the 2006 model. He said he had a 2007?

[Lunddude]

Originally Posted by jrdonicht

I see the part but that part is only listed for the 2006 model. He said he had a 2007?

I do have a 2007 & according to my motor ser.# part #10 is what I have in my motor. Not sure where your seeing that it's only for a 2006 but I'm pretty sure the 07 & 06 are probably the same as long as it's a 4S EFI. For what it's worth I've been told that Yamaha built the power heads for some Mercs & I think my motor may have a Yamaha power head with a Merc lower unit.

[jrdonicht]

Originally Posted by Lunddude

I do have a 2007 & according to my motor ser.# part #10 is what I have in my motor. Not sure where your seeing that it's only for a 2006 but I'm pretty sure the 07 & 06 are probably the same as long as it's a 4S EFI. For what it's worth I've been told that Yamaha built the power heads for some Mercs & I think my motor may have a Yamaha power head with a Merc lower unit.

I just goggled that restrictor plate part number and it only came up for the 2006 model. It probably is for the 2006 and up. Your serial number will tell it all. Sorry I am just very curious of the outcome of this upgrade. I cannot wait to here the results. Hope it works out for ya.

[tv4fish]

All three motors with the exception of the gearing in the 115 are basically the same

Don't think you will have any problems at all - Merc has been doing that for a few years. ) Back in the mid 90's, I bought 2 different rigs - one had a 75 hp and the other was a 90 - the only difference affecting the hp output was the larger carbs that the 90 had.

[Lunddude]

Just spoke with Eric a few hours ago. He's got my ecu and is doing the remap today and will be able to get it back to FedEx this afternoon. I sent along a pre paid over night shipping label so with any luck I should see it tomorrow. He claims after the remap the motor will be putting out closer to 120HP and figures I should be able to keep runing my 15P prop and should hitting some where in the 6000+ rpm range @ my 5000'elv. I'm hopeing to run at least the 15P and if the rpms are high enough I'll throw the 17P back on that the 75 was runing @ sea level while turnimg 56-5700 rpm. I'll post results after I've had a chance to test her out

[NWwalleye]

Very interested .. Keep us posted .

I have a Yamaha 80 hp 4 stroke, was considering this a few years ago. Just never did it.
Might consider it now.

[Lunddude]

Well my reflashed ecm showed up this afternoon from Simon Motor Sports. It's now been reinstalled on the motor and the restrictor ring has been removed. I went a head and put the muffs on her and fired her up in the driveway.

All I can say is I can't wait until I put her in the water tomorrow morning! The motor definetly sounds more throaty with the reflash & the restrictor ring removed we are definetly getting some AIR now!

Reminds me when I upgraded the turbo on my 7.3 PSD & stepped up to the AFE Stage 2 from the AFE Stage 1 air intake, moving way more air makes for a Happy motor @ altitude.

I went through all the functions on my Merc Monitor & all systems are go. The motor still idles @ 720 rpm and Troll Control lets me drop her down to 550 rpm. I think the motor actually idles better now at 550 rpm then she did before the reflash.

Stay Tuned!