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RUNWME

What kind of speed ? 89 River Rocket 362 hp Merc?

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Based on Power to Weight Ratio...which is not exact but fun anyway

362 HP : 1400#

= 122 mph

362 HP : 1300#

= 127 mph

I think those numbers would be a good estimate

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We shall see, picking up the engine this weekend. The guy I am getting from said he ran 118 GPS in Quarter shot with he and his wife. He was running low compression heads (150 psi) at the time so HP would have been lower then 362 (dyno with high compression heads)

Either way should really spank the 103 my carb 2.5 is laying down.

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My CALCS are based on weight, excluding driver...I still think you can do 120's.

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I am excited about it! I want to run over 125 and win the 500.00 posted on Scream and fly awhile back. If 362 horses wont get me there... Chuck Goodman will!!

Easier to pay Chuck for nitrous then for me to give up Taco bell and lose weight!! lol  One thing for certian, with me sitting in front, blowovers arent a worry!!

David

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A minor bubble burster but it ain't 362. Thats the powerheads output and not the prop shafts output.

The engine I bought was dynoed at 340 with high comp heads. Didn't want that nitemare and got regular gas heads.

Was told this would give me about 280-290 hp. I guess I can live with that. When I can't a change of the heads and OOmph.

This is a modified racers engine, don't know exactly what was done to it.

Firewalker has said in the past that this kind of power will get 120 if not 130.  I suppose this power is really meant for acceleration or load capacity since I believe these speeds are over the boats limits?

Besides some have posted extremely high speeds but won't give up the secrets, this on Euros!

362 is a substantial increase over a 260! But I don't think it's 100 hp?

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Drove to 8 hrs to pick up the engine, then 8 hrs back. I reinstalled my 10 in jijacker plate so I could put this 15 in offshore mid on the back of my 20 in River Rocket.

I get the motor mounted, hooked up, fresh batteries in the GPS yesterday and crap! Can't mount the hydraulic steering because the tiller arm is too short. Looks like I may need an adapter (anyone have one?)

Engine is a  2000 S3000 dragblock. He had reciepts for approx 10,500 spent on this engine with Diamond marine setting it up for modified production class.  It has been lightened, ported, rod slots opened,diamond tuner, JSRE flywheel ect ect.

I got with 3 sets of heads, 150compression 180 compression and 220 compression

I installed the 180 lbs compression heads because they were on it when dynoed.

If I can find an extension for my tiller arm, I will be boating this week and will post numbers I get things setup.

I didnt want to set the motor that far back, but was only way to mount this midsection. How much is this much setback going to hurt performance?

Thanx

David

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DAVID...

10" does seem like a lot of setback...but who knows till you try...might be OK...the only real shortcoming might be the extra weight which could slo down acceleration, but top end should not be affected...also the 10" may want to force the nose up a little more ...but fly it stern high and nose flat and it should be OK.

PLAY SAFE and make sure you wher all your safety gear and tether on!

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362, is at the flywheel.....even from Diamond. I saw the motor over on scream and fly.

That motor is likely more like 310 at the prop.

10" is a lot of setback and hardly ideal for top end. Becareful.

Merc makes a spacer for the tiller arm.

What bottom do you have, in 89 you COULD have a sprint.

RT

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The first picture is old, but shows the bottom. Is this a sprint bottom?

I bought this engine for drag racing and don't mind running racing fuel in it.  My plan is to run the 300drag 1 weekend a month at the race and mount my 2.5 carb for tooling around with the family.

I changed the interior and made it into a 4 seater to make my wife happy (versus 3 with centersteering)

I have to weigh 1800 lbs for Lake Racer class with this engine.

Anthony, you said the extra weight might slow me down for acceleration, what extra weight are you referring to? The jackplates are within 2 lbs weight of one another.  I was thinking the extra setback may would allow the engine better leverage and lift the boat up quicker for acceleration, but I will admit my thinking could be flawed...

post-2-1058829816.jpg

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OK.. going to fire on the hose tonight and make some passes with it tomorrow.   I hope it lays done some respectable numbers.

Just curious firewalker, how does mercury rate there engines? At prop or powerhead?  I was thinking they rated at the prop. If a stock drag engine makes 300 at prop. And a diamond modified (for 10k more  dollars) one makes 310 at prop. That equates to a 1 thousand dollars per 1 horsepower. OUCH!!

wish me luck! I feel like a kid in the candy store I am so excited to try it out.

post-2-1059146538.jpg

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All OBs after some year were rated at the prop. But if your talking about an engine on the dyno there isn't a prop on the dyno. When you say power head this isn't an Outboard.

I kind of question the large loss of power though. I thought it was much less than Firewalker said.

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I just bought a Merc service manual for my 260. It says that the 2.5efi makes 280 crankshaft hp and 260 propshaft hp. Similarly, the 2.5 carb lost 20 horses from crank to prop shaft bringing it down to 245.

Just thought it was interesting info.

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SPEED RESULTS...

I havent replied and let you know how it was running because I was constanly changing engine height , props , fuel mixture ect. Best combination is 1 3/8 above the pad with 10 in setback plate and spinning a Ron Hill 30 lab cleaver. This prop wasn't fastest out of the hole, but midrange punch and higher it really flew!

After several 8000-8500 rpm blasts pushing the boat edging my way up through the 1teens I finally held the throttle for an extended time screaming to about 9300 rpm before engine stopped accelerating. GPS  126 MPH !!!  EGT recall max temperature 1280.  Engine temp reach 164 degrees Pretty close to neutral on the trim.

WOW what a rush!!

I do not like 10 inches of setback in low speed driving, but seems to work fine at higher numbers and it has no porpoise above 40 mph.

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You may have the fastest STV on bored now...congrats!!!

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Thanx guys! It comes after several years of owning hot boats and wishing for more speed.  I have 47 more months of payments on this engine (boat is paid for)  so I hope it holds up.

The greatest thing about this engine is the acceleration through the midrange (and ofcourse the top speed) It will turn a borrowed 26 prop 9800 RPM and will bury 10k tach with a 22 drag yammi.

I pulled the heads and see no residue and think the engine may be too lean. I do see alittle scorching (red and black discoloration at top of piston around exhaust port.

It ran best numbers with A63 box set at 99% but I am going to turn it to 105% to cool down exhaust temperatures alittle bit. In addition I am going to back the compression back to 150 so I dont have to keep buying 4.00 per gallon fuel.  I know richening mixture will slow me alittle, but how much top speed will I give up dropping compression 30-40 lbs?

Anthony, I doubt I have the fastest STV on the board though. 7 people said they ran over 120 mph on the poll Helmut was pushing mid 120s I think with his 260 powered Euro!

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RUNWME,

Definately Impressive speeds...your sprint seems to rock on top end!!!!  You're definately one of the fastest now.

Stay safe.

Jamie

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