Prop for 4.3l merc I/O 22.2 ff aquasport

[sebas54]

Hi, I need to replace my Propeller But don't know what size I need. I just bought this boat in the spring and the guy who sold it to me, told me he went through 4 props before finding one which worked well.

I have all 4 props but the one thats on the boat, I don' tknow what size it is.

I go 23 mph at 3900 rpms with my prop now.

I would like to go faster if possible. Thanks

It's a 175HP 4.3L merc I/O
1980 22.2 feet family fisher aquasport

I don't know anything about props so I am looking for somebody to tell me exactly what I need.

Thank you.

Also I can post the size of the other three props but don'y know what to look for.

 

[steelespike]

Re: Prop for 4.3l merc I/O 22.2 ff aquasport

I'm not an expert but I'll get you started.
First there should be numbers on all the props something like -- X --
diameter X pitch. Lacking that there should be a part number.
You should Check the motors compression and proper tune.
Your present performace is low. Don't know your motors specs but performance should be about 4,500 rpm with speed depending on which prop is best.29 is quite low.It's not good for the motor to operate so far below the
normal WOT(wide open throttle) specs.See if you can get all the prop numbers and motor condition. And get back to us.

 

[Silvertip]

Re: Prop for 4.3l merc I/O 22.2 ff aquasport

Look at the barrel of the prop (between the blades) for number such as 13 x 19P (13 inches diameter, 19 inches of pitch). Those numbers may also be on the face of the prop behind the nut. If you don't see those numbers, look in the same areas for a Name and or a series numbers (e.g., a part number). Thats the only way to tell what you have. Then post those numbers, as well as the numbers (and the name if available) from the other three. You may have one that works. The one that's on the boat now is not allowing the engine to run in its 4500 - 4800 rpm range so its 600 - 900 rpm low. But before you get all concerned about props, make sure the hull is clean (not full of algae or barnacles. Make sure the engine is tuned and making full power. And also make sure the throttle is opening fully. No sense messing with carbs if the engine isn't making full power. Just saying it runs smooth does not mean it doesn't need a tune up. Especially if you have no idea when it was tuned up last.

 

[sebas54]

Re: Prop for 4.3l merc I/O 22.2 ff aquasport

Thanks for the replies. When traveling at 3900 RPM's the engine is not at WOT. The person who I bought the boat from told me not to go above 3900rpm's. He told me that I would blow the engine. There is still some room left in the throttle. Anyway, I will post the specs of the props tommorrow. Is there any way that I can Identify the prop's spec with it in the water? Thanks again!

 

[Bondo]

Re: Prop for 4.3l merc I/O 22.2 ff aquasport

I have all 4 props but the one thats on the boat, I don' tknow what size it is.

Ayuh,....... So what are the Other 3 props,..??..??....

The 4.3l should be turnng about 4400/4600rpms at WOT.........
And,.....
Nope,..... You probably Can't read the #s on a prop on the outdrive, in the water......
Not without getting Very Wet...........

Btw,........... Is this the Same boat you had the Head off of a few weeks back,..??....

 

[sebas54]

Re: Prop for 4.3l merc I/O 22.2 ff aquasport

Well I found two of the props that didn't work and these are the part #'s
48-832832-c1 L S
48-78120-10 L J

I'll get the third and post the part # tomorrow.

Bond-o, yes this is the same boat that I have been trying to fix for some time know. Well I finally finished it. I am going to reply to the other posts to update them. After changing the man/riser, getting a valve job, new plugs, new starter and 2 oil changes she runs. That grinding noise that I was trying to figure out was not the fly wheel; it was indeed the timing and valve adjustment. The actual grinding noise was the start spinning continually, I think that I tightened the valves too much and the dist. cap was off. I fixed that and she runs as good as ever. Thanks for all the help and encouragement.