Motor takes a few seconds before high RPM

Locomofo79 created the topic: Motor takes a few seconds before high RPM

My cat has been acting up lately, in the turns it bogs down really bad. When I get in the straightaway it takes about 2-3 seconds before the RPM start to kick in.. It's like the power band takes a while to kick in.. I thought it might be my pipe but I shortened it and made it longer.. My carb is set to 1 1/8 H and 1 1/2 L.. Any help is greatly appreciated.
#19790

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Ronald Olson replied the topic: Re: Motor takes a few seconds before high RPM

Try adjusting the strut depth by going a little higher with it. In the turns the boat may be leaning enough to where it's dropping the prop further into the water. If it's too high then it will free up in the corners.
#19793

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Locomofo79 replied the topic: Re: Motor takes a few seconds before high RPM

Thanks for the reply, I'll be sure to adjust the strut up 1/8 at a time until it cavatates, than bring it back down until the cavatation stops. What's your view on the straightaway? If I start out just in the straight and WOT it hangs up as if i was at half throttle for 2-3 secconds sometimes longer and than all of a sudden it starts spinning crazy RPM's. I think it's a pipe issue I can't resolve due to lack of knowledge. When I hit the really high RPM (tiny tach says 19,748rpm) any turn I make drags the RPM down to half throttle.. I'm about to throw the engine away!! :angry:
#19801

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Ronald Olson replied the topic: Re: Motor takes a few seconds before high RPM

OK, let's go back to where things should have started, the basics of what you have such as which Cat, prop or any other thing that we may need to know. Some Cat's need the strut at certain heights and it can be a factor. What prop?
The engine sounds like it's turning at a good RPM so we'll throw that out of the equation.
#19802

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smokeater2005 replied the topic: Re: Motor takes a few seconds before high RPM

Along with the basics, which is a good idea for us to get a handle on what could be wrong... I know this is going to sound stupid but it sounds like you have a loose hardware problem. I have a 1/8th scale ofna ultra GTP with about 1000$ in upgrades and it did the same thing to me coming off of a tight turn or a jump... it turned out to be a loose mounting plate under the upgraded two speed trans which u cant tell till you take like a billion things off/loose... Anyway point being check all points that move, slide, spin, or conduct electricity, and the mounts that are connected to the before mentioned action points. and if u have no doubt about it NOT being the carb, or prop placement and basic setup are ruled out then maybe think about a looky inside the engine/rebuild, or cheaper yet do an engine swap from another and see if this fixes the problem? just some thoughts...
#19803

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Locomofo79 replied the topic: Re: Motor takes a few seconds before high RPM

I have the Stryker TG Cat with Speedmaster strut and rudder setup. I have the power master tune pipe (wet pipe) with 1" dia header. The have tried several props (6717/3 stock & mod, 2716/3 mod & 7014/2 7016/2) but nothing seems to help resolve the problem. I figured the small diameter prop would help but nothing worth getting excited over. My carb is the wt-771 and the settings are 1 1/8 H & 1 1/2 L and when the rpm finally turn up it's nice and crisp. The low end sounds great but it seems like it struggles to get past this one spot for the rpm to whind out. I have a video but it's .mov format. I'll send it to your personal if that would be fine with you. I'm WOT the whole time on vid and you can tell exactly what I'm talking about. Let me know, thanks..
#19819

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boatking replied the topic: Re: Motor takes a few seconds before high RPM

did this just start , or have you had this problem from day 1?also it would help to take some pic,s of your set up (front,back,side,engine bay)
#19820

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Ronald Olson replied the topic: Re: Motor takes a few seconds before high RPM

Amuse us and take the low-speed needle out to 2 turns and see what happens. You seem to be typing about a transition issue here.
I'm not saying that it's the cure but it just might help.
#19822

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mitchesx replied the topic: Re: Motor takes a few seconds before high RPM

I had a boat like this, I never actually found the problem. If the low end adjustment doesnt work, check your ISO block on a table for any gaps, the gaskets, etc. How is your fuel setup? Is it a hard tank or bag? Is the bag able to move if you have one? If its a hard tank, is the pickup off the bottom or is there a leak? Have you replaced the lines? I have also seen radio issues cause a problem like this, finally getting to a point where it shut the boat off in the furthest corner (failsafe). Just thinking out loud here.
#19824

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Locomofo79 replied the topic: Re: Motor takes a few seconds before high RPM

Ronald Olson "you are da man"!!! That was the problem, adjusted the strut and that thing is singing.. Put the bigger prop 2717 mod and got 67.6mph.. Makes turns at WOT and no rpm bog down..

Thanks Again
#19825
The following user(s) said Thank You: Ronald Olson

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