Motor reving but i go nowhere

[CollinCountyCab]

This might sound crazy but I can only see 2 motor mounts. The aft ones. Took a flashlight and tried to stick my big arm under motor but can not see or feel any other mounts. I wouldn't even think thats possible....I want to align the motor properly especially before I dump $700 in a Skat Track double swirl impeller

 

[racerxxx]

Bust out the mirror and the flash light and start looking, there better be at least one more in the front.

 

[CollinCountyCab]

Do the seats come off? Im gonna search removing seats

 

[CollinCountyCab]

Gear reduction question.......Now we're really going to test the jedi master minds.......
The original location of the GSXR drive sprocket goes to a another drive which is attached to a larger sprocket which then goes to sprocket on the PTO. It's not 1-1 so what is the final reduction percentage? I will count the teeth on the sprockets tomorrow. Anyone have the formula to then take that fraction to RPM'S?

Motor may be turning at 5000 RPMs but what is my impeller spinning at? On a direct drive RPM's from engine should match impeller, right? My setup has different size sprockets. Good luck on that one! Here is a photo of the crazy chain setup...

 

[CollinCountyCab]

UPdate..... loosened the motor mounts and "muscled" the motor over a bit...BAM. Lined up 100% better. Drive shaft went in and out super easy. I also ordered the PTO boot.
Still have to figure out the impeller pitch. This is up for sale...any offers??

 

[CollinCountyCab]

should look a lot better

 

[CollinCountyCab]

Any math wizards out there....here's the teeth count on the sprockets so I can figure out shaft RPM's in relation to motor RPM's

 

[CollinCountyCab]

QUESTION-- If there is no cavitation problem but you needed to rev motor high in forward (4000RPM) to get thrust...what would you look at for the "problem?"
Resealing pump and getting rid of carbon seal fixed my cavitation problem (i think) New wear ring and dremeled the edges of impeller so do I need a new impeller all together? Current one is the original, verified by number on side of impeller. I think it's a 13/19. Thoughts? I would like it to jerk me out of my seat instead of a top speed record. If I could get it to do "wheelies" that would be cool.
Thanks in advance.

 

[racerxxx]

How fast is it at top speed? Have you gps'd it? I mean if you're running wfo and are going 52-54 mph you're pretty much right there where you want to be.

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[CollinCountyCab]

only went fast for a few minutes....will gps this weekend and see top speed. i guess in my head I think a motor capable of spinning 13k RPM it should do 70mph.

What do I know??
Thanks for all your assistance.

Will sell this boat to anyone who posted on this thread for $2800 cash money!! $3400 for everyone else.

 

[racerxxx]

Any math wizards out there....here's the teeth count on the sprockets so I can figure out shaft RPM's in relation to motor RPM's

Calculating this is a mess. But a dirty way of doing it is mark the engine sprocket at the vertical. Mark the driveshaft at the top. Rotate the engine sprocket 1 full revolution and how far the driveshaft rotates.

Now, I'm not 100% certain how to run through all the sprocket sizes but......

The engine sprocket is 17t (t = teeth) and the one it drives is 20t so that has a final ratio of 1.176:1 So the engine sprocket will turn 1.176 time to 1 rev of the 20t

So the 20t is back to back to the 30t so that is a final ratio of 1.5:1 So 1 rev of 30t should be 1.5 of the 20t (again you can mark it and check that)

So the 30t is connected to the 19t on the PTO....Final ratio of 1.579:1 so the 30t will rotate 1 time to 1.579 times of the 19t sprocket. So I "THINK" the drive shaft is rotating roughly half a rev (or maybe a full rev?) faster than the engine sprocket. So at a lower RPM the impeller will be spinning faster. If the logic in my brain is working properly. But again a simple line on the sprocket and shaft will get you that.


Now, what I'm not 100% sure of is...Is one engine revolution = to what on the engine sprocket? And is that relative. So, if that is a 6 speed box what is the final ratio and how is that related to RPM.

This is all just a mess that typed from my brain. To calculate the ratio just divide the big sprocket by the smaller sprocket. 20/17=1.1764

I could also be way off in left field. Anyone is more than welcome to tell me I'm way wrong and I will not doubt you.:banghead:

 

[CollinCountyCab]

Calculating this is a mess. But a dirty way of doing it is mark the engine sprocket at the vertical. Mark the driveshaft at the top. Rotate the engine sprocket 1 full revolution and how far the driveshaft rotates.

Now, I'm not 100% certain how to run through all the sprocket sizes but......

The engine sprocket is 17t (t = teeth) and the one it drives is 20t so that has a final ratio of 1.176:1 So the engine sprocket will turn 1.176 time to 1 rev of the 20t

So the 20t is back to back to the 30t so that is a final ratio of 1.5:1 So 1 rev of 30t should be 1.5 of the 20t (again you can mark it and check that)

So the 30t is connected to the 19t on the PTO....Final ratio of 1.579:1 so the 30t will rotate 1 time to 1.579 times of the 19t sprocket. So I "THINK" the drive shaft is rotating roughly half a rev (or maybe a full rev?) faster than the engine sprocket. So at a lower RPM the impeller will be spinning faster. If the logic in my brain is working properly. But again a simple line on the sprocket and shaft will get you that.


Now, what I'm not 100% sure of is...Is one engine revolution = to what on the engine sprocket? And is that relative. So, if that is a 6 speed box what is the final ratio and how is that related to RPM.

This is all just a mess that typed from my brain. To calculate the ratio just divide the big sprocket by the smaller sprocket. 20/17=1.1764

I could also be way off in left field. Anyone is more than welcome to tell me I'm way wrong and I will not doubt you.:banghead:

Your ears are SMOKIN!!!!

 

[CollinCountyCab]

Headed to the lake!!!!!

 

[CollinCountyCab]

Ran good. I REALLY need to find the right impeller. Going to try a smaller one for SUPER low end. I'm also going to try and install a thru hull exhaust for that great header sound!!
Thanks again to everyone who helped me out!

 

[racerxxx]

What speeds did it show on gps?

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[CollinCountyCab]

Soooo....here's what happened. I get to the ramp and we still have the deck lid off so I start it on the trailer and 7 peeps come up to chat. 6 Bud lts later and an hour later. i forgot to GPS but....I did have it up to 10k RPM. Super fun for sure.

 

[CollinCountyCab]

Flushing out the cooling system and changing out some of the older hoses with new ones. Getting it all ready for daily summer fun!!

 

[CollinCountyCab]

I couldn't get the "radiator cap" off the heat exchanger. After a couple of bangs with the hammer...I broke it! I ordered a billet aluminum weld on "neck." Off to the aluminum welder on Monday! Antifreeze looked great in it though......am going to flush out system while waiting for parts to come back. What pressure cap do you think I need? 13lbs?

 

[CollinCountyCab]

broke clean off....

 

[racerxxx]

That's a new one, never used a hammer to take a radiator cap off. Sorry, couldn't resist.

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[CollinCountyCab]

i couldn't turn the cap. TAP, TAP, TAP.......CRACK!!