Videos of High Output Aluma Jet

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: Videos of High Output Aluma Jet

I always wonder how long the engines will last when pushed as hard as Yamaha does.
i had me a wave runner with the 140hp version of the mr-1 engine. wot rpm was 10k rpm. i had me a few mods on mine and got 10,200 rpm out of mine. i'll have to agree with ya though, it worried me too. that's really some fast rotating parts. i think they get that kinda rpms by keeping the stroke short. i just looked up the spec. bore x stroke= 2.91" x 2.28". man, that piston isn't hardly going up and down.
anyways. i had 235hrs on my mr-1 w/o any issues at all. i've heard them lasting quite long if cared for. that said. i got rid of mine partly because i couldn't believe it can be so durable spinning that fast.
fwiw, if i remember right. the r-1 engine, same as the mr-1 but for bikes wot was 1400 rpm. the sport shop guy i worked with when i had my ski said they can run that long for ever and 10k rpm was way under what they were capable of sustaining.
 

andyk2

Cadet
Joined
Jul 24, 2011
Messages
7
Re: Videos of High Output Aluma Jet

I don't get the comparison. There is probably 1500lbs difference between the two. Put that little boat up against a 250 HP jetski and see what happens. Just as pointless.
 

scooper77515

Senior Chief Petty Officer
Joined
Sep 3, 2010
Messages
753
Re: Videos of High Output Aluma Jet

i agree, the weight difference is ruining the "experiment". I had a 400 lb jetski, 110 hp, it would hop OUT of the water if gunned from sitting still, then still hit 60 mph in around 2 or 3 seconds. SCARY ride.

Lots of engine and hardly any weight.
 

PSG-1

Seaman
Joined
Jul 17, 2011
Messages
50
Re: Videos of High Output Aluma Jet

I love the performance of Yamamha's newer jet drives but I always wonder how long the engines will last when pushed as hard as Yamaha does.

I've heard of some of the guys on PWC forums who claim 3,000+ hours on their Yamaha 4 strokes.

As far as mine, it was used, but it only had like 68 hours on it!! Not a spot of corrosion anywhere on the engine, it's like brand new! My engine came out of one of the Yamaha jetboats, it was one of 2 that a friend of mine had in his shop (he works on, and recycles PWC's)

So far, I LOVE this engine! As I said in my video, WAY better than that old 2 stroke Tigershark 1000 that was previously in the boat.

I took my girlfriend out on the river the other day, we ran it 30 miles over a 2 hour period, occasionaly at WOT, and occasional idling, but generally about mid-range.... and it burned about 6 gallons. So, that's 5 miles per gallon, or 3 gallons per hour for the fuel consumption. As the boat has 2 11 gallon tanks, that's roughly 6 hours of runtime, or about 85 miles cruising range.

Not only does it burn less fuel, but it is quiet, and it doesn't smoke like a 2 stroke. I can't wait for winter trout season this November, this boat is gonna be perfect for trolling grubs and mirro-lures! I caught trout with it, even with that noisy 2 stroke, so now, I ought to really be able to stealth up them.
 

PSG-1

Seaman
Joined
Jul 17, 2011
Messages
50
Re: Videos of High Output Aluma Jet

@ ziggy:

When I first read the specs on the engine, I thought "no way this XL1200 pump will hold up to 10 grand" but then I read on and saw that the engine uses a 1.47:1 reduction gear, which steps the impeller RPM down to around 7 grand. (This reduction gear also causes a 'chatter' at idle in the VX and FX engines.)
 

PSG-1

Seaman
Joined
Jul 17, 2011
Messages
50
Re: Videos of High Output Aluma Jet

@ andyk2:

It's basically a comparison showing the acceleration of the jetboat. Although that Sea Hunt is a heavy boat, it's maxed out on HP (it's rated for a 150) and it's pretty fast out of the hole, too.

Also, bear in mind that jet drives are NOT as efficient as propellor drives, jet drives are approximately 45-55% efficient at power delivery. (I base that statement on a spec given in a Sea Doo jetboat manual for the Speedster with twin 85 HP engines. It states that HP at the jet unit is about 35 HP. Check other manuals, and you'll see the same kind of figures as well.)

That means that a 160 HP engine with a jet drive, actually has about 80 HP at the impeller. While propellor drives may not be 100% efficient, either, they certainly are higher than 60% efficient. I'm not sure exactly what percentage it is, I'm just going to guess and say probably 65-70% efficient. So, given that, a 150 HP engine might have about 105-110 actual HP at the prop.


But since you mention comparing it to a jet ski......I just so happen to have a Yamaha VX110, so, maybe I'll do a short video showing that against the jetboat, and we'll see what we come up with. Either that, or I can race it against my Yamaha Super Jet.
 

NSBCraig

Lieutenant Commander
Joined
Aug 21, 2007
Messages
1,907
Re: Videos of High Output Aluma Jet

Yeah but the two boats are completely different!

So the comparison is pointless.

Put any number of boats up against the jet and it will lose all around!
 
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