Testing the Allison Grand Sport with a Mercury 150 Four Stroke

[Wave to Wave]

Was wondering if you'd gotten them installed and been back out, have you talked to Simon about the tuning and what rpm peak hp is made?
According to the CARB report it's at 5400rpm for the standard and 5500 for the Pro XS version though I've always ran fastest right up to the limiter and had heard they were detuned which is why Mercury bumped the limiter on the Pro XS version which is claimed to make 5 hp more and more torque because of the transient spark though the report shows the same hp and torque...
https://www.arb.ca.gov/msprog/offroa...001-0476-1.pdf

Do you happen to know the guy claiming 77mph in this thread?
https://texasfishingforum.com/forums...boat_top_speed

By feel, the XS mounts seem a little stiffer, but keep in mind it is just the uppers that are different, so it is not significant. It really needs solid mounts, still quite sloppy. I think only one other Allison ran the 150 four stroke, a ProSport, but I could be wrong.

I was wondering if the Racing V8 mounts would fit on the V6? That's interesting about the Sportmaster. I have a project in mind for that engine! Racing should have done a 225R V6!

[Wheelman]

By feel, the XS mounts seem a little stiffer, but keep in mind it is just the uppers that are different, so it is not significant. It really needs solid mounts, still quite sloppy. I think only one other Allison ran the 150 four stroke, a ProSport, but I could be wrong.

I was wondering if the Racing V8 mounts would fit on the V6? That's interesting about the Sportmaster. I have a project in mind for that engine! Racing should have done a 225R V6!

I agree and believe they will as the part numbers for the standard mounts between V6 and V8 are the same, looking forward to that one as well.

[xb03fs]

Coned lower will make all the difference. I would spend my money on this before worrying about the other mounts....

Getting the motor up and correct and the correct balance inside the boat are the most important aspects.

[Wheelman]

Coned lower will make all the difference. I would spend my money on this before worrying about the other mounts....

Getting the motor up and correct and the correct balance inside the boat are the most important aspects.

I understand the nose cone will help prevent blow out by lengthening lower unit and increase speed by lessening drag, but do you want to raise an outboard up higher because you now have low water intakes and increase the risk of a blowout because of soft mounts? Curious of your specific experience with the Mercury 150hp 4-stroke if you don't mind sharing.

[xb03fs]

Call me this weekend and we can talk. 314-323-6036

[Wheelman]

Call me this weekend and we can talk. 314-323-6036

Good talking to you, didn't realize Glenn Reynolds is the gentleman who ran the original Allison w/ 150hp 4-stroke...
http://www.bbcboards.net/showthread.php?t=49516
http://www.mercuryracing.com/pro-max-prop/

[Wave to Wave]

Older thread but I realize I never updated it after the modifications we talked about. With the coned lower, which I modified a couple times, I rounded the tip mostly. I hit 80 MPH with a 30" Promax prop. That's with the propshaft 1/4" below the pad. There is probably a little more in it if I run it higher. It's running great though. Can cruise beautifully in the 60s and 70s. Gets unbelievable mileage, around 10 MPG in the low 40s and close to 7 in the 60s.

There have been some new Grand Sports being built and rigged with the newer 150 ProXS, and one might be running 1.75 gears, so that one will be easily above 80.

Article
https://www.wavetowave.com/home/2019...=project%20150

[fishnfireman]

[M4A1]

That is one gorgeous boat.

[Mikes250r]

Yes that is a beautiful boat!

[BASSBUZZ]

Seen on The Hull Truth boat is for sale. $44k

[Wave to Wave]

Seen on The Hull Truth boat is for sale. $44k

Yes, listed a few days ago. Can message me directly for more info.