Question about WOT?

[_chris_]

Re: Question about WOT?

Also found this, it is from baylinerownerclug.org

first of all, it is not the shaft that changes in length between the 250/270/275 and 280/290 SP and so on style...... Well, actually the shafts are of different lengths..... but with the proper spacer installed, the exposed shaft section is the same....... it does not affect which propeller can be used. (it gets confusing for many)

The length of "exposed" shaft (from the spacer back) is dictated by the spacer/line cutter....... this is different for each drive.

NOTE: 250/270/275 must use the spacer/line cutter for that drive.... you cannot use the long spacer.
Conversely, the 280/290/SP and so on must use the spacer/line cutter for that drive...... you cannot use the short spacer.
Stay with the correct spacer, and the exposed shafts are same.

Short spacer/line cutter on the 250/270/275 ..... long spacer/line cutter on the 280/290/ SP and so on style!


But I'd think of more importance to your question is propeller hub style/length.

You will find two hub lengths that each require a different cone nut (spinner).
Short hub/long hub!
There are two types of "spinners" ..... one "full" spinner...... one multiple part spinner!
The multiple spinner works on either propeller hub..... ie; long or short!

For example:

The long hub propeller fits either style drive (w/ the correct spacer), but the spinner for the long hub is used w/out the forward piece, and it reaches inside of the female splines of the hub some.

The short hub prop fits either style drive, but the spinner is the full one (or the two piece with both halves being used).

Here is a spinner (cone nut) that does both short/long hub props.
It's machined for the center locking bolt, so it will do the 275 and later shafts. It is also relieved for the SS locking tab.



Bottom line.... don't get hung up on hub length..... just use the two piece spinner and you've covered for either prop.

 

[hwsiii]

Re: Question about WOT?

Then all you have to do is measure the shaft and we will know what we need.


H

 

[_chris_]

Re: Question about WOT?

From those examples I found online I have a short hub. Hope this helps.

 

[hwsiii]

Re: Question about WOT?

OK Chris, let me see what I can find for it.


H

 

[45Auto]

Re: Question about WOT?

Trying to make sense of what you guys are doing.

WOT is supposed to be 5500 RPM.

You're currently turning 4900 RPM at WOT with a 15" pitch prop.

You're proposing going to a 17" pitch prop in hopes of INCREASING the WOT RPM to 5500?????

Only way you'll get to 5500 RPM is to drop the pitch down to 11" or 12". No way that boat should have to have a prop that small on it. Either something is wrong with your RPM number or your prop pitch number, or you have engine problems that all the prop changing in the world won't fix.

When's the last time a complete, COMPETENT tune up and compression check was done on the engine? If it's still original, it could be getting a little tired after 37 years ......

 

[hwsiii]

Re: Question about WOT?

The specifiations I have for that motor show a WOT RPM of 5,100 RPM, is that wrong.


H

 

[junior1113]

Re: Question about WOT?

Trying to make sense of what you guys are doing.

WOT is supposed to be 5500 RPM.

You're currently turning 4900 RPM at WOT with a 15" pitch prop.

You're proposing going to a 17" pitch prop in hopes of INCREASING the WOT RPM to 5500?????

Only way you'll get to 5500 RPM is to drop the pitch down to 11" or 12". No way that boat should have to have a prop that small on it. Either something is wrong with your RPM number or your prop pitch number, or you have engine problems that all the prop changing in the world won't fix.

When's the last time a complete, COMPETENT tune up and compression check was done on the engine? If it's still original, it could be getting a little tired after 37 years ......

agree with 45auto engine is weak, boat is water logged, or bottom of hull is dirty. so this boat only spins 4900 with one person? how is condition of of prop. going to a 13 would probablyh work to get rpms up but that would be making up for another issue. if that motor was strong i would say a 17 should work

 

[_chris_]

Re: Question about WOT?

Trying to make sense of what you guys are doing.

WOT is supposed to be 5500 RPM.

You're currently turning 4900 RPM at WOT with a 15" pitch prop.

You're proposing going to a 17" pitch prop in hopes of INCREASING the WOT RPM to 5500?????

Only way you'll get to 5500 RPM is to drop the pitch down to 11" or 12". No way that boat should have to have a prop that small on it. Either something is wrong with your RPM number or your prop pitch number, or you have engine problems that all the prop changing in the world won't fix.

When's the last time a complete, COMPETENT tune up and compression check was done on the engine? If it's still original, it could be getting a little tired after 37 years ......

The head was rebuilt about 8 years ago and the block about 5, A complete tune up was done 2 years ago and this year I have rebuilt the carbs and done plugs, wires, cap and rotor. She runs very well. Compression was checked last year and was good, I can not remember off the top of my head what it was.

The specifiations I have for that motor show a WOT RPM of 5,100 RPM, is that wrong.


H

I believe you are correct.

 

[junior1113]

Re: Question about WOT?

The specifiations I have for that motor show a WOT RPM of 5,100 RPM, is that wrong.


H

hi h, i show 5000-5500 recomended wot rpm but as we know the engine will run better and last longer at upper limits of recomended range.

 

[bigskiohio]

Re: Question about WOT?

17 or 19 I would guess 19 for all around but somthing sounds fishy here

 

[_chris_]

Re: Question about WOT?

agree with 45auto engine is weak, boat is water logged, or bottom of hull is dirty. so this boat only spins 4900 with one person? how is condition of of prop. going to a 13 would probablyh work to get rpms up but that would be making up for another issue. if that motor was strong i would say a 17 should work

Prop is in good condition with no dings dents or bent. 4900 was with two people weighing total of 400 LBS and 18 gallons fuel.

 

[_chris_]

Re: Question about WOT?

If I went to the 17 or 19 how would it change things? Is it worth it?

 

[hwsiii]

Re: Question about WOT?

Paul and 45Auto will you please show me where you got the specifications for recommended WOT operating range of 5,500 RPM as mine shows 4,600 to 5,100 RPM with a gear ratio of 2.15:1, and if it is 5,500 RPM then my numbers are wrong.
Chris would you please look on the engine for a sticker, some of the time they have one.
I still believe we can use a 17" pitch and gain RPM, but if that engine is supposed to be turning 5,500 RPM we need to find where the problem is, because there is a problem if it is supposed to turn 5,500 RPM


H

 

[hwsiii]

Re: Question about WOT?

Paul and 45Auto will you please show me where you got the specifications for recommended WOT operating range of 5,500 RPM as mine shows 4,600 to 5,100 RPM with a gear ratio of 2.15:1, and if it is 5,500 RPM then my numbers are wrong.
Chris would you please look on the engine for a sticker, some of the time they have one.
If that engine is supposed to be turning 5,500 RPM we need to find where the problem is, because there is a problem if it is supposed to turn 5,500 RPM


H

 

[_chris_]

Re: Question about WOT?

I will check it out when I get home today but I don't think any of the original stickers even say anything anymore. I will also talk to my grandfather he was the original owner up until two years ago when I picked it up.

 

[hwsiii]

Re: Question about WOT?

Sounds Good.


H

 

[_chris_]

Re: Question about WOT?

Ok I just got off the phone with my Grandfather and he still has all the original paperwork on the boat, In the owners manual it says that the WOT RPM for the AQ130c is 5100 unless it is in a smaller boat with speeds that can reach 35 MPH then it is safe to go to 5500. I think this is where the confusion came from because Volvo states both so I think it all depends on the boat. I would love to hit 35.

 

[hwsiii]

Re: Question about WOT?

After reading that information it just verifies my statement earlier that you should be going faster. You definitely have a light boat, and should be reaching 35 MPH. Either the motor has a problem or the prop, and it doesn't appear to be the prop.
Check the butterfly valve in the carburetor to make sure it is opening all the way and pull the plug wires one at a time to be sure the engine stumbles when you pull them and I would check the timing advance as well. There is a problem with the motor Chris.


H

 

[_chris_]

Re: Question about WOT?

So with the prop I have I should be reaching 35?

I will go through it this Sunday, check everything from compression to the carbs and let you know what I come up with.

 

[hwsiii]

Re: Question about WOT?

Probably not, maybe 33 MPH but a 17" pitch will reach 35 MPH.


H