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Community Stats
- Group Members
- Active Posts 15
- Profile Views 6,322
- Member Title Novice
- Age 50 years old
- Birthday November 16, 1974
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Gender
Not Telling
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Location
Bridgenorth,(Near Peterborough) Ontario, Canada
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Interests
Bikes, cars, ATV's, boats, snowmobiles, basically anything with an engine. And since I live in Canada, I play and watch hockey whenever I can fit it in.
Previous Fields
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Year of DOO
2000
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Model of DOO
Speedster 160
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Engine in DOO
Mercury Mē Jet Drive 240 EFI
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State or Province
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Website URL
http://
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Posts I've Made
In Topic: 4-tec
25 May 2005 - 02:04 PM
In my speedster, if you want to do a spinout, just keep the throttle pinned and turn either full right or full left and hold on! That is one of the coolest feelings. The boat feels too big to be dooing it, but it works great!
In Topic: twin 215hp Speedster?
21 April 2005 - 07:34 AM
I think the hull of the 200 is only rated for 370 and that's why they detuned the supercharged engines. I wonder what you have to do to bring them back up to 215 each.............
In Topic: Rev Limiter RPM Increase
18 April 2005 - 03:29 PM
It's been a long winter! I meant to check back more often, but hanging out in here just makes me miss the doo!
In Topic: Rev Limiter RPM Increase
18 April 2005 - 12:24 PM
Getting back on topic, raising the rev limiter without dooing other modifications is not going to help. Every engine, but especially 2 strokes, have an RPM where they produce their peak horsepower. If you have a dyno chart to look at, you will see the horsepower curve up and up and at some point, it must change direction and curve down. The highest point of the curve is where the manufacturer takes their horsepower reading and they usually give an RPM as well. The prop or impeller selection for a boat is usually made from that figure.
For example, let's say you have a boat making 240hp at 5300rpm. If with a 19 pitch prop (propeller moves ahead 19 inches every revolution) running at wide open on the lake with one person, almost no gas, slight ripple on the water etc. you notice that your tach says 5500rpm and you are doing 60mph. You could change to a 20 pitch prop and bring the rpm down and your speed up as you will be closer to the peak hp of the engine. Just remember, with a 20 pitch, on a day with some chop, full tank of gas, 5 people, etc. the boat may be slower.
But also, the rev limiter on that boat from factory is probably set at 5700 rpm, so even if you change it to 6200rpm, it won't make any difference. The only way it matters is if you change the porting, pipe, compression ratio etc. and change the point at which the engine makes its power. Then even after changing the rev limiter, you may have to change prop/impeller to take full advantage of the change. The only reason that sea-doo's and sea-doo boats have rev limiters is for when you launch them out of the water or cavitate badly and there isn't enough water drag to slow the impeller down.
For example, let's say you have a boat making 240hp at 5300rpm. If with a 19 pitch prop (propeller moves ahead 19 inches every revolution) running at wide open on the lake with one person, almost no gas, slight ripple on the water etc. you notice that your tach says 5500rpm and you are doing 60mph. You could change to a 20 pitch prop and bring the rpm down and your speed up as you will be closer to the peak hp of the engine. Just remember, with a 20 pitch, on a day with some chop, full tank of gas, 5 people, etc. the boat may be slower.
But also, the rev limiter on that boat from factory is probably set at 5700 rpm, so even if you change it to 6200rpm, it won't make any difference. The only way it matters is if you change the porting, pipe, compression ratio etc. and change the point at which the engine makes its power. Then even after changing the rev limiter, you may have to change prop/impeller to take full advantage of the change. The only reason that sea-doo's and sea-doo boats have rev limiters is for when you launch them out of the water or cavitate badly and there isn't enough water drag to slow the impeller down.
In Topic: Mercury 240 impeller upgrades
23 November 2004 - 11:20 AM
I also feel that the Hydrosurge works and I would like to keep it, but reading about all the failures had me ready to buy a fixed tine. One day I got talking to my buddy who has manufactured a few cool things for me before, and he said it would be no problem to make a grate from stainless steel, and we are going to look into replacing the comb style spring with a wound style.
My first idea was to just get the stainless grate built and just replace the comb spring every year so it wouldn't be in danger of breaking, but they cost over $75 up here! So I figured with a wound style spring, even if it breaks, it will stay around the front hinge bolt and not go through the jet drive. We'll see if it all works out, and I will post some pictures once we get the whole thing built.
My first idea was to just get the stainless grate built and just replace the comb spring every year so it wouldn't be in danger of breaking, but they cost over $75 up here! So I figured with a wound style spring, even if it breaks, it will stay around the front hinge bolt and not go through the jet drive. We'll see if it all works out, and I will post some pictures once we get the whole thing built.
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