Props

[ulises646]

I have a 1997 22ft sea pro citation with a 1997 mercruiser 5.7 with a 2bbl carb. Can you suggest the right props? Someone had recommended 15 inches but a friend said using a 19 inch will give me more speed. Please help.

 

[Bondo]

Re: Props

Ayuh,... Welcome Aboard,... Answer these few questions, 'n We can help ya,....

 

[jestor68]

Re: Props

The trusty Merc prop calculator says:

Dry weight=2800 600lbs of people/gear. 40 gals of gas totals 3628 lbs.

Using a 1.47 gear ratio, it says 14.5 X 19 in 3 blade or 14.5 X 18 in 4 blade.

Using a 1.62 gear ratio, it says 14.25 X 21 in 3 blade or 14 X 20 in 4 blade.

 

[ulises646]

Re: Props

wow!!! by that calculation being that my boat wight 2750lb I'm using the wrong props...what I'm using is 15.25 x 15.
aluminum. This means I need to sell these asap they are still new only used them for about a month.

Thank You so much!!! if you have any recommendation of anything else please let me know as I'm new to the boat world..

 

[jestor68]

Re: Props

What sort of full throttle rpm were you turning with the 15 pitch prop? That is the best info to put into the prop calculator, along with the gear ratio of the outdrive.

These selections are based on a new motor making like new power. Your older motor may not actually be able to use that much pitch.

We need to know what it's doing now in order to advise on the correct pitch.

 

[ulises646]

Re: Props

The boat has difficulty coming out of the hole and the rpm will start at about 3500 and once it comes out of the hole (sometimes 3 to 6 min after) it will slowly increase rpm to about 4300. And it wont go more then 40 mph.

 

[jestor68]

Re: Props

The boat has difficulty coming out of the hole and the rpm will start at about 3500 and once it comes out of the hole (sometimes 3 to 6 min after) it will slowly increase rpm to about 4300. And it wont go more then 40 mph.

STOP! Don't sell that prop just yet. Since your recommended full throttle rpm range is 4400-4800, and you can only get 4300 with a 15 pitch, your motor is not putting out full power for whatever reason.

I would not waste money buying another prop until you sort out why that motor isn't developing the power that it should.

I would have it checked over by a Mercruiser tech to see what the problem is. Given that it's a 1997, it might be that it's just getting tired. Hopefully, a good tune up might get it going. It should be able to accelerate out of the hole strongly and spin that 15 pitch prop past the 4800 rpm limit.

 

[ulises646]

Re: Props

sound like a plan. I will do that asap. I had a tuneup done replace cables, plugs, distribution cap, rotor, oil, rebuild the carb...I tried setting the time using a light gun and setting it to 10 on the harmanic wheel. Sometimes the RPM will go above 4500 when I play with the ignition timing. I will have to take it a mercruiser tech...

 

[jestor68]

Re: Props

sound like a plan. I will do that asap. I had a tuneup done replace cables, plugs, distribution cap, rotor, oil, rebuild the carb...I tried setting the time using a light gun and setting it to 10 on the harmanic wheel. Sometimes the RPM will go above 4500 when I play with the ignition timing. I will have to take it a mercruiser tech...

There is a special procedure for setting the initial timing on a thunder bolt ignition equipped motor. Let the Tech do it. He can also check to see that the timing is advancing as it should.

Who did the tune up?

 

[ulises646]

Re: Props

Honestly? I did. reading on line and watching video can really help a lot. Just like blogging with you about this.

 

[ulises646]

Re: Props

Hello, I want to thank all for helping me with what ever you can. I changed my props from a 15 to a 19 and the boat were still doing the same just that the boat now just go to 3200 rmp. I took it to a mechanic and they checked the compression on the cylinders and they all show from 80 to 90 psi. I don't want to rebuild this engine yet but I want to be able to get some speed or power on this. What do you suggest? Should I go back to the 15 inch prop since the engine is not putting all the power or maybe less?

Also after changing all the gaskets on the drive now i'm getting water coming out of the steering wheel cable or harness when the boat goes above 2800 RPM...Please HELP ME. I spent 3 month remodeling this boat and I'm just about done with so much work and hours put in to this boat. Thanks

 

[steelespike]

Re: Props

Yes go back to the 15. At least it puts you close to the wot rpm if you reduce pitch anymore you will be even slower top end.
Can't help much on the steering cable except that it would seem there is a problem at the outdrive end of the cable.A seal at the end or a bad casing.

 

[ulises646]

Re: Props

Yes go back to the 15. At least it puts you close to the wot rpm if you reduce pitch anymore you will be even slower top end.
Can't help much on the steering cable except that it would seem there is a problem at the outdrive end of the cable.A seal at the end or a bad casing.

Thank you for helping out.... I noticed that the mechanic was checking the compression on the engine by just removing one spark plug and just ckanking onces....after cheking on youtube i noticed that is a totally different process then just removing one spark plug....so im sure the reading was wrong. He did adjusted the spark plugs, timed the ignition and changed the gimbal bearing.

Now after checking the boat in the water is running just fine...rpm goes up to 4800 with the same prop (19s) and the boat comes out of the hole fast.

With the steering wheel water leak i notices that the power steering fluid was completely empty after realizing that i never added fluid after replacing a power steering hose. I added power steering fluid and that fixed the problem.

What do you think?

 

[ulises646]

Re: Props

Yes go back to the 15. At least it puts you close to the wot rpm if you reduce pitch anymore you will be even slower top end.
Can't help much on the steering cable except that it would seem there is a problem at the outdrive end of the cable.A seal at the end or a bad casing.

Thank you for helping out.... I noticed that the mechanic was checking the compression on the engine by just removing one spark plug and just ckanking onces....after cheking on youtube i noticed that is a totally different process then just removing one spark plug....so im sure the reading was wrong. He did adjusted the spark plugs, timed the ignition and changed the gimbal bearing.

Now after checking the boat in the water is running just fine...rpm goes up to 4800 with the same prop (19s) and the boat comes out of the hole fast.

With the steering wheel water leak i notices that the power steering fluid was completely empty after realizing that i never added fluid after replacing a power steering hose. I added power steering fluid and that fixed the problem.

What do you think?

 

[steelespike]

Re: Props

Checking compression is pretty basic you can remove one plug at a time and crank it till the pressure stops going up.
If he cranked each cylinder for about 10 seconds I think it should be enough.
You may have water in the power steering system see if the fluid looks creamy.