Aint Got No Power

Ok, my 760 I just built has me baffled. All new parts, ported cylinder, B-pipe/mod chamber, new stock cdi, new stock coil, factory stator, factory flywheel, dual 46 Riva Red tops, 62t cases, brand new V-Force 2 reeds, blah blah blah. Ok, lets get to the nut cutting. It has no power.........it runs like a 440. It will only pull rpms if I jump it and unload the pump. When it loads back up in the water it takes off like a bat outta hell for just a second then the rpms drop and it runs like a 440 again. I thought that maybe the woodruff key was broke throwing the timing off but thats not the case. I have had it in and out so many times that I am wearing the bolts out. We build motors all the time and have never ran into this. Could it be a problem with the stator? It is the original off the ski (1994 SN). It sounds electrical but all is new but the stator and flywheel. Has anybody else had this happen before? I thought about msd total loss but if I dropped the $1200 and it did the same thing I would probably just burn the damn thing to the ground. Ok engine gods........lets here your thoughts.
 
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Sounds like you may have the wrong prop. Alot of times when machines are modified, the prop that used to work, no longer works. Also, since you did port the engine, the stock timing may be an issue, is this a 760 cylinder, or a big bore?

The prop issue happened to me only once, it was on an SXi, ran great in limited form, but we SS'ed it, and had the issue you mention. turned out we had to re-prop. It was the first and only time this has ever happened to me. One other thought, a possible mis-index of your crank, this also happened on the same freaking machine. We got a crank from a reputable shop, tried for TWO years to figure the thing out, it would run okay, just not what we thought was right, finally my buddy let me send the crank off for inspection, viola!

Hope this helps...
 
I don't think its the crank or the impeller. I am running the same impeller (13/18 free ride swirl Scat Trac) that I was running with a stock 701. And I have used two different cranks with the same setup. I'm gonna go with the only things that I haven't replaced yet:bigeyes: Well looks like I'll have to sell a kidney and buy the MSD total loss:scared: Something else I noticed last night is that the bearings in the mid shaft housing are making a lot of racket:thinkerg: Thats probably where my loss of power is happening :woot:

PS

Its a stock bore (84mm) 62t cylinder
 

FX-6.9 Boy

VILLIGE IDIOT
I think your cramalation fluid is not flowing through the cramalators properly thus causing it to cram in the cramhole too slowly..........I know, too technical right?
 
Location
Mahopac, NY
It sounds like a fuel problem. If it revs when you hop the ski out of the water and once it hooks up if falls flat on it face. I think you are to rich. Try using a tach and get a intial rpm then turn your high's in like a half a turn and see if your rpms go up or not. If they go up then you have a rich condition. But you need to be careful don't lean it out too much. Once you start to get close go in at about 1/8 of a turn. That way you don't squek the motor. But the what you are describing sounds really rich and half a turn shouldn't do any damage.

Matt
 

yamahammer

are you men the police?
Location
San Angelo, TX
It sounds like a fuel problem. If it revs when you hop the ski out of the water and once it hooks up if falls flat on it face. I think you are to rich. Try using a tach and get a intial rpm then turn your high's in like a half a turn and see if your rpms go up or not. If they go up then you have a rich condition. But you need to be careful don't lean it out too much. Once you start to get close go in at about 1/8 of a turn. That way you don't squek the motor. But the what you are describing sounds really rich and half a turn shouldn't do any damage.

Matt



I am pretty sure he's not too rich. He's spent about $4000 on a boat this summer that hasn't run 5 minutes. Ohhhhh wait not that kind of rich. We have tried 2 sets of carbs and every imaginable size of jets, n&s, and popoff we could get our hands on. ITS CURSED.:banghead: DAMMIT!!!
 

yamahammer

are you men the police?
Location
San Angelo, TX
Thanks for all the advice guys (with the exception of fx-fag, scrotumhammer, and nonutsforme) I think I found my problem. The intermediate shaft bearing sounds like your crunching up potato chips when you turn it. :bigeyes: I got all the parts coming, now if I can just get the damn thing apart:thinking:

We all know how much your fatazz loves potato chips! Dont get hungry and eat your intermediate shaft!!!......................no i have nothing better to do at work:haha:
 

FX-6.9 Boy

VILLIGE IDIOT
:loser: :loser: :loser: :loser: :loser: :loser: Why don't the two of you eat your computers and get your azzes back to work!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 

THRUST

ThrustInnovations.com
if its not your intermediat try your plug wires sounds like possibly you are losing a cylinder check plug caps .new msds or if stock there could be a break in the wire that will make it fire intermittent . tell us what you found
 
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