seems like something is holding me back.....

[sinbad jr]

Ok so I decided to put my boat in the shop I was told that the motor was only running on 3 cyl and not the normal 6 cyl because it wouldnt go over 2200 rpms(They replaced both switches). So I take it for a bay run and now it gets up to about 5100 rpms,
now the problem is when it gets to about mid trottle (2200rpms) it dosent want to go like something is holding me back, but when I pass the 22 2300 mark it opens up good smoooth..... the carbs are in great shape middle and bottom are new and top was rebuilt and works good also. The fuel pump and everything that goes with it is new. Can anybody please help me with this problem? Whats with the hesatation sputtering

 

[gss036]

Re: seems like something is holding me back.....

I would suspect it would something to do with the change over from low speed to high speed jets. If you just push it to full throttle does it still hesitate?

 

[sinbad jr]

Re: seems like something is holding me back.....

no it runs great at full

 

[gss036]

Re: seems like something is holding me back.....

I was referring to putting it at full throttle from the beginng, does it hesitate as it passes the 22-2300 rpm range?

 

[sinbad jr]

Re: seems like something is holding me back.....

the carbs are brand new so I dont think it has anything to do with that.
I think its electrical like the sator is messed up from only running on 3 cylinders for so long............the wires are soft...

 

[sinbad jr]

Re: seems like something is holding me back.....

no it dosent

 

[jmburock]

Re: seems like something is holding me back.....

ONe culprit that you might overlook are the switch boxes- I assume you have 2 on your motor.

 

[sinbad jr]

Re: seems like something is holding me back.....

I changed both switches when it was in the shop.

 

[sinbad jr]

Re: seems like something is holding me back.....

Could it be a fuel problem or is it electrical?

 

[CharlieB]

Re: seems like something is holding me back.....

Are you running a 'vented' prop?

A 'vented' prop allows a measured amount of cavitation on hard acceleration from low speeds to allow the engine to rapidly gain RPM into the engines 'power band', as boat speed increases the water speed past the prop seals off the vents and the prop gets a better bite into the water.

Running 'slightly lean, and I mean just barely lean at idle, the prop cavitation/slip may not show the symtoms of a lean idle, yet running @2200 you may be just past the cavitation point of the vented prop and the lean idle may show as a small hesitation, or bog until engine RPM is well off the idle circuit and getting into the mains.

Depending on your carbs, fatten the idle mixture screws 1/8 turn CCW to slightly richen the idle and try it again.

The fact that it runs great from idle straight to WOT shows NO fault in the ignition system, and that the fuel system is very close to ideal.

 

[sinbad jr]

Re: seems like something is holding me back.....

so are you saying that a vented prop is good? If you mean vented as in exsust in the center of the prop right behind the lock nut yes it has that.

 

[sinbad jr]

Re: seems like something is holding me back.....

gss036
I notice it now does what you were refering to there is a bog from the start to full throttle. So what do ya think it is?

 

[gss036]

Re: seems like something is holding me back.....

Possibly just switching from low speeds jets to the high speed jets. The jets in the carb are fixed.
Sometimes surging is caused by too much water in the water seperating filter, gas floats on top of the water, but in choppy water it gets mixed and causes the surge because you are not getting clean or enough fuel.

 

[sinbad jr]

Re: seems like something is holding me back.....

It sounds like what your saying I'll look into it. The fuel pump is new so I hope its not that...................Thanks for your help I'll let you know how it goes. And thanks to everyone else who added there input............