Otseg

The Mercury rule of thumb is up to 85 MPH use the HD gear case and over 85 MPH the Sportmaster gear case with its low water pickup.

Surfing the internet I have not yet found anyone claiming over 80 mph offshore with quad 300 Yamaha's. Reported speeds with the quad 300 Yamahas seem to hit the wall below 75 mph.

So the question is; Why?

bills106

Only one reason I can think of, because you haven't tried it yet!

ed d

Beat me to it , I scrolled down to see my response . Happy Holidays Guy's

They got that Lake and Bay single Nizpro 450 going pretty good which was a Yam 300 LU , if this it about LU's .

Otseg

Yes. I suppose it is a gear case question.
I never got to ride in my friends Cobra with Yamaha's. He wrote the ad and his boat was used for the photo shoot. I assume that girls ass caught up with her after they slowed down.

nautiboyz

I used to be obsessed with those cobras.

Clamcove23

I like where this might be going!
are you saying you are thinking about
attempting this on one of your builds?!

Great Outdoors

Damn- looks like the perfect boat.

bsh102

Jaguar Marine ? The World?s Finest Custom Powerboats
32’ with twin 300 will do 80
43’ with quads is a 95mph boat
I have been playing with one of these 32’ in my mind for awhile.

bluejack

"I assume that girls ass caught up with her after they slowed down."

This wins the internet for me today. Classic

I thought I heard screaming mercs a few weeks ago (pre xmas) from my house way back up Choco bay, fully expected to see updates. Guess it coulda been Reggie. Have y'all run this latest one yet?

mbb

Has "Quad 300 Yamaha" and "Over 80 MPH" Ever been Used in the Same Sentence Before??

You just did.....so at least once.

Fordy

Y

Y

Team Seaside

Nobody's put them on a 17 whaler yet?

Otseg

Perhaps the question is, how high can you run the stock Yamaha 300 gearcase and still make sufficient cooling water?
This High?

Clamcove23

wow that looks like the skeg is the only thing
fully in water!
is that one of your boats with mercs on it?
i know it’s not but, looks like a piece of plywood and a shingle
as a mounting wedge!!

Pineapple Express

I'm pretty sure that that Osteg was using plywood while he was dialing in the setback and mounting height of the motors. I believe this boat has since been fitted with jackplates.

Clamcove23

haha!
after re-reading my post it sounds like a typical snarky THT remark,
not my intention.
i have full confidence in anything Jim would do, and figured it was for
testing reasons.
good to know sometimes it just comes down
to a couple pieces of scrap wood to be able to dial in 70-80mph!!

Otseg

Actually 90 to :-) mph

You fit the standard HD case which Mercury recommends if your expected top speeds are under 85 mph. We expected more with quad 400r's and saw well over 90 with the sport master gear case and off the shelf Bravo 1 propellers. Must have low water pickup as pictured. A remote water pick up voids the warranty. I know I can modify the Yamaha gear case to get water with the engine mounted as high as I want to, But I don't need warranty issues. Good to know how high I can mount the engines with the standard gear case and make the transom the right height before hand.

Yamaha good for up to ?? mph



Mercury offshore HD good up to 85 mph





Mercury Sportmaster good for over 85 mph



1.25 to 1 overdrive gear case from a 1970's outboard water speed record Hydro good over 150 mph. My finger points to the water pickup below the bullet, 1/4" x 1/2". No water pump.

Clamcove23

Thanks for the info otseg,
not something I’ve ever worried about
but after reading some of your builds
i can see how placement of water pickups
starts to come into serious play!
good stuff

Otseg

So far its like searching for your 10mm socket to get any info.

Clamcove23

Just looking at pickups seems like Yamaha
might be similar to merc HD?
you should test it on one of your hulls!!
ill pay!