Alpha one gen 1 questions

[j cat]

Last summer I was out on the boat. Noticed a kind of ticking coming from rear end of boat. I heard the same if you spin the prop out of the water. I was taking it easy coming back to shore and I heard a bang then lost all thrust. When boat is in gear it wants to die. However neutral it runs. I drained lower to check for metal shavings but didn't notice anything too out of the normal. Any ideas what couldve broke?

I inspect in the fall on the alpha1 top cap.. now If I found some water drips I have to fix the out drive with a leak... the small O ring top/bottom has the oil movement top to the bottom ...has that leak...I put a 7-10psi on the top oil port with an air gauge and also I replace the water pump assy then inspect the air pressure for 24 hrs..
when I replace the oil I drain the bottom port ...remove the top cap... then I put new oil on the top cap then the old oil drains out and then it looks like new.. then I put the bottom plug locked up then install 34oz ....
your picture looks nasty ... put mineral sprints in your outdrive .. put it on the top cap.. then drain it out then fill it up to min spirits take a day or so then drain it and then install and the inspection parts..
back in the old days I used engine oil to flush out the old oil ... then put the correct drive train oil fluid ....

 

[Hlumley07]

I inspect in the fall on the alpha1 top cap.. now If I found some water drips I have to fix the out drive with a leak... the small O ring top/bottom has the oil movement top to the bottom ...has that leak...I put a 7-10psi on the top oil port with an air gauge and also I replace the water pump assy then inspect the air pressure for 24 hrs..
when I replace the oil I drain the bottom port ...remove the top cap... then I put new oil on the top cap then the old oil drains out and then it looks like new.. then I put the bottom plug locked up then install 34oz ....
your picture looks nasty ... put mineral sprints in your outdrive .. put it on the top cap.. then drain it out then fill it up to min spirits take a day or so then drain it and then install and the inspection parts..
back in the old days I used engine oil to flush out the old oil ... then put the correct drive train oil fluid ....

I just purchased a whole new drive assembly from sei. About ready to install. I noticed after removing the old drive there was some white deposits left. Any recommendations on something to run through it to clean it? Also I am looking for a new prop that will give me lower rpm at higher speed. Currently has a 19p on it. Thank you for all your help

 

[nola mike]

I just purchased a whole new drive assembly from sei. About ready to install. I noticed after removing the old drive there was some white deposits left.

Where?

Also I am looking for a new prop that will give me lower rpm at higher speed. Currently has a 19p on it. Thank you for all your help

Probably should start a new thread in the prop section, but you want to choose your prop pitch based on your WOT rpms; should be 4400-4800 rpm, at the higher end when lightly loaded.

 

[Hlumley07]

Where?

Probably should start a new thread in the prop section, but you want to choose your prop pitch based on your WOT rpms; should be 4400-4800 rpm, at the higher end when lightly loaded.

Will do. I will post a picture tmrw but its on the housing where the upper attaches. All in where the shift cable is and where the water flows not sure what the port is called

 

[achris]

... Also I am looking for a new prop that will give me lower rpm at higher speed. Currently has a 19p on it. Thank you for all your help

This will overloaded the engine and drive. It will burn the oil in the drive, and lead to premature engine failure (holes in pistons and/or burnt valves, blown head gaskets, etc)... It will not save you anything in fuel, and will make the boat feel sluggish and unresponsive. It will be a dog 'out of the hole' and be difficult to drive in any sort of swell...

To get the best results from your engine (for reliability, longevity, economy and 'driveability') choose the propeller that, when the boat is normally loaded, allows the engine to run to 4400 to 4800 rpm at wide open throttle. And the closer to the top of the range the better. My own engine will bang on the rev limiter at wide open. This idea of 'use a bigger prop and save fuel' is completely false (I've done the trials and have the graphed results if you'd like to see them), and just makes engine repairers rich, or sells Merc a new power package....

Chris...

 

[rustybronco]

Also I am looking for a new prop that will give me lower rpm at higher speed. Currently has a 19p on it. Thank you for all your help

All due respect to those who have years of experience but what prop did the boat come with from the factory? My boat the boat came with a 13.75 x 21P prop yet the one that was on it was a 14.25 x 19P. I'd find that information first and move forward from there.

 

[j cat]

I just purchased a whole new drive assembly from sei. About ready to install. I noticed after removing the old drive there was some white deposits left. Any recommendations on something to run through it to clean it? Also I am looking for a new prop that will give me lower rpm at higher speed. Currently has a 19p on it. Thank you for all your help

on the new out drive flush out a engine oil on the top cap see if it is any metal on the lower plug. then inspect the 7-10 psi to see if the pressure does not drop for a few hrs... I do my alpha 1 !!! ..
your boat is a 18ft 165HP your boat is 1900-2600lbs ? the alum prop 15-1/4 in DIA,,,,,, 21in pitch ...looks like 41-47 MPH...
the stern drive gear ratio is 1.65:1 ............your engine is the max rpm 3900-4300...

my wellcraft 20ft 1978 is 3000 lbs , my outdrive is 1.84 ratio my prop is 15-1/2in ,, 19in pitch .. my eng rpm to the max is 4000rpm ...33MPH.. deep hull ..
I have my OEM mercrusier manual ...

 

[Rick Stephens]

All due respect to those who have years of experience but what prop did the boat come with from the factory? My boat the boat came with a 13.75 x 21P prop yet the one that was on it was a 14.25 x 19P. I'd find that information first and move forward from there.

I like the answer.... but respectfully I submit, over time an older boat gets heavier, the hull gets dirtier with scratches and wildlife stuck to it. It gets less efficient torque output from an older motor. It gets (sometimes random) stuff added to the inside. It is really tough to go by any boat manufacturers spec at time of rolling off the line.

Besides, this boat owner already has a prop. So he/she can get the boat out on the water, first, do the drive break in. Then, do a Wide Open Throttle RPM and GPS speed test on calm water. This will tell all without guessing or triangulating from what it had out of the factory 25 or 30 years ago.

 

[rustybronco]

And over time the prop can get damaged being less efficient. We don't know.

The reason for the statement, and I still stand behind it, is a starting point to see if what you have is somewhat in the ball park. If the manufacturer called for a 17P prop of a certain diameter and you have a 19P prop on it, you can begin to suspect something else my have been changed in those 25~ 30 years.

For instance. My drive shows on the decal a serial number that doesn't match what's shown on the cover a top the engine. The decal shows the proper ratio for the craft but I still counted the teeth on both upper gears just to be certain. The craft shows evidence of minor repair to the keel? of it. That combined with the drive change makes me want to question everything in that regards including prop diameter and pitch.

 

[achris]

And over time the prop can get damaged being less efficient. We don't know.

The reason for the statement, and I still stand behind it, is a starting point to see if what you have is somewhat in the ball park. If the manufacturer called for a 17P prop of a certain diameter and you have a 19P prop on it, you can begin to suspect something else my have been changed in those 25~ 30 years.

For instance. My drive shows on the decal a serial number that doesn't match what's shown on the cover a top the engine. The decal shows the proper ratio for the craft but I still counted the teeth on both upper gears just to be certain. The craft shows evidence of minor repair to the keel? of it. That combined with the drive change makes me want to question everything in that regards including prop diameter and pitch.

I think you're missing the point completely.

Unlike cars, boat builders rarely put the engines in themselves. Heck, most of the time they don't even know which manufacturer's engine is going in!

The choice of engine (make and model) is up to the dealer, or even the retailer. And they also get the option of which drive ratio to install.

So, customer comes in and says I'll have 'that' boat. Salesman asked which engine. Buyer says 'Ke?' So then it's up to the salesman to work out what to put in. Once the engine and drive is installed, the installer (usually one of the mechanics out the back) should be taking the boat for a test drive, and that is when the correct propeller should be selected. That's what SHOULD happen. What usually actually happens is the guy out the back just looks at the boat, engine and drive ratio, checks the wind direction and strength, and has a stab in the dark that it needs an 'x' pitch prop (diameter it determined by the prop manufacturer and isn't usually 'customer selectable').

TL;DR, Manufacturers don't determine the prop, that should be done by the retailer. And they is no 'standard prop' for a give boat/engine combination. Unlike cars, every boat is different and hence the prop will be different.

The only right way to select a prop is to take the boat out on the water and test run them. That goes equally for a 20+ year old boat with a rebuilt engine, or a new engine as much as for a new boat with a new engine.

Chris.........

 

[Hlumley07]

The white deposits is what I'm referring too. I ended up buying a 14.25 19p prop

 

[achris]

The white deposits is what I'm referring too.

Someone's been running leaded fuel... Those white dots are where metallic lead has settled on the aluminium and has set up a galvanic cell and caused corrosion...

I ended up buying a 14.25 19p prop

With a view to changing it if it's too big, I hope....

Chris...

 

[Hlumley07]

Someone's been running leaded fuel... Those white dots are where metallic lead has settled on the aluminium and has set up a galvanic cell and caused corrosion...

With a view to changing it if it's too big, I hope....

Chris...

What do you mean too big? The diameter? The original is 14.8 manufacturers recommend replacement is 14.5. All I could find is 14.25

 

[Bondo]

What do you mean too big? The diameter? The original is 14.8 manufacturers recommend replacement is 14.5. All I could find is 14.25

Ayuh,..... Diameter is a function of blade design,....

Ya shop props by Pitch,....

 

[Rick Stephens]

Too big refers to pitch. Diameter is somewhat mushy topic and usually matters little except whether the prop clears your drive - performance from various diameter props depends on how any given prop, manufactured by whoever, and how aggressive the cup, progressive the pitch, and many other factors combine. Most of us ignore diameter for the most part.

 

[Hlumley07]

What do you mean too big? The diameter? The original is 14.8 manufacturers recommend replacement is 14.5. All I could find is 14.25

I stand corrected 14.25 is too big. It hit the anode

 

[Bondo]

I stand corrected 14.25 is too big. It hit the anode

Naw, you just need a different anode,..... they make several styles, just for that reason,.....

An Alpha drive can swing, Almost 16",......

 

[achris]

I stand corrected 14.25 is too big. It hit the anode

Take a file to the anode and make it fit. (That is the OFFICIAL recommendation from Merc BTW)...

 

[j cat]

I stand corrected 14.25 is too big. It hit the anode

the prop port moves , creates a move to the rear of the rubber shock .
then the prop blade hits the anode ..also a spacer on the drive shaft , the move more to the rear to hit the anode . spacer could be thicker to go further back ..

 

[achris]

It's not a spacer, it's a thrust washer, and each prop has it's own thrust washer so to set the prop at the correct position for the labyrinth seal to operate properly. Don't mess with the 'depth' of the propeller on the propeller shaft. Use the right thrust washer for that prop and leave it at that.

Chris.....