Keep getting spun prop 1969 Evinrude 18hp

[1969FastwinNewb]

I'm sure there is an obvious answer to this that will embarrass me but this is my first project outboard. I have a 1969 evinrude fastwin and I have spun 2 hub when revving up to top it out. It ran great at half throttle but when revved up, I lost power, boat bogged down and I was only able to limp along afterward, about half speed. The first time I really spun it out because I had no idea what it could be. Same thing happened to me yesterday when I put an older and reportedly good prop on it, ran about 0.25milew and bogged down when I revved all the way up, leaving it permanently less powerful.

I have replaced the impeller and water pump housing, it sprays water like a firehouse out the exhaust. Rebuilt card twice, reset the point gaps along with new condensers, the engine runs clean and fires up easy.

The propeller came with a washer that I don't know how to put on because there is not enough room on the propeller shaft... My 1969 owners manual does not show the washer though and the prop came off a 1958 18hp so maybe that's where the washer came from.

I then bought a new propeller and when I went to put it on, but it seems like the internal hub is not pressed in far enough to catch on the key that locks into the propeller. I can push the prop on tighter but when it catches on the key finally, it cannot spin freely. And it grinds the metal. Please help me figure out what's going on, I have really enjoyed getting this thing running but it's just been one thing after another.

 

[racerone]

You have inspected the clutch dog and forward gear lugs?----Made sure that shift rod connecter is assembled correctly ?----Made sure shift rod is adjusted correctly at the shift handle ?----You bought the new prop at a dealer or " on line " ?

 

[1969FastwinNewb]

You have inspected the clutch dog and forward gear lugs?----Made sure that shift rod connecter is assembled correctly ?----Made sure shift rod is adjusted correctly at the shift handle ?----You bought the new prop at a dealer or " on line " ?

I have not taken apart the gearcase, can you elaborate on what I would be looking for regarding the clutch dog? How would it be causing this just so I understand the problem. I have re-sealed the lower unit in my 1958 18hp so I at least understand how to take apart and put back together.

The new prop was from a prop shop btw

 

[kbait]

i have heard of spun prop bushings on newly re-hubbed props due to not following ’break-in or ‘hub set’ procedure. If I remember correctly (from tag on freshly re-hubbed prop from shop),with gearcase in water over 70 degrees (I used barrel in garage as it was early spring), start motor and shift f-n-r for about 5 minutes at idle. Keep below 1/3 throttle for first 10 minutes of operation in lake, again shifting f-n-r several times. Then hub should be ‘set’ and ready for normal use. I believe new props are pre ‘set’ at factory, but rehabbed from propshop are not. Good luck!

 

[1969FastwinNewb]

i have heard of spun prop bushings on newly re-hubbed props due to not following ’break-in or ‘hub set’ procedure. If I remember correctly (from tag on freshly re-hubbed prop from shop),with gearcase in water over 70 degrees (I used barrel in garage as it was early spring), start motor and shift f-n-r for about 5 minutes. Keep below 1/3 throttle for first 10 minutes of operation in lake, again shifting f-n-r several times. Then hub should be ‘set’ and ready for normal use. I believe new props are pre ‘set’ at factory, but rehabbed from propshop are not. Good luck!

That is very interesting and helpful. I'm going to try to file or machine this new one down just enough to fit back far enough on the key and spin freely, then see how it does. I kind of wondered if there was a break in, this is just something I don't know anything about. There are no instructions that came with this new one. It is a solas Amita 3 , 9 x10 aluminum prop

 

[tphoyt]

If it’s not right maybe take it back to the prop shop and confirm that. Sadly I have purchased stuff that was junk right out of the box. Poor quality control does exist maybe you got a bum prop.

 

[kbait]

That is very interesting and helpful. I'm going to try to file or machine this new one down just enough to fit back far enough on the key and spin freely, then see how it does. I kind of wondered if there was a break in, this is just something I don't know anything about. There are no instructions that came with this new one. It is a solas Amita 3 , 9 x10 aluminum prop

I have used a few new solas props without breaking in the hub-with success. Again i believe all factory-new props will be ready to go, but prop shop re-hubbed would need break-in. Either way, breaking in cannot hurt

 

[1969FastwinNewb]

I have used a few new solas props without breaking in the hub-with success. Again i believe all factory-new props will be ready to go, but prop shop re-hubbed would need break-in. Either way, breaking in cannot hurt

Awesome, thank you!

 

[roscoe]

I'm confused.
You say the prop hub spun, and then the engine bogs down.

That is the exact opposite of what typically happens with a spun prop.
Engine will usually rev high.

 

[1969FastwinNewb]

I'm confused.
You say the prop hub spun, and then the engine bogs down.

That is the exact opposite of what typically happens with a spun prop.
Engine will usually rev hi

I meant that it bogs down in speed, the sound of the engine revs super high and the speed drops off simultaneously. When I let off the throttle all the way and then rev back up slowly, it runs again but there is an obvious lack of power afterward. Then I'm basically limping it along the rest of the time

 

[1969FastwinNewb]

Just to be clear, is there anything anyone can think of that could be going on in the gearcase or anywhere else that might cause the hub to spin more frequently. It has only happened when I am running nearly full throttle but it has happened twice, both within the first 0.25- 0.5 miles in the maiden voyages. I understand I may have had the misfortune of having 2 bad props in a row but I'm skeptical of that and inexperienced enough not to know if I'm missing a common root of this problem other than worn down hubs.

 

[kbait]

If prop is not binding against gearcase housing and spins freely in neutral, nothing in gearcase would cause a spun hub bushing.

 

[1969FastwinNewb]

If prop is not binding against gearcase housing and spins freely in neutral, nothing in gearcase would cause a spun hub bushing.

Awesome, I will update when I can get a new prop on and see if this happens again. Fingers crossed that all is well. Thanks everyone!

 

[1969FastwinNewb]

Well just so everyone is aware, I had the trim set too high. I got with a family member and we adjusted the trim and took it out. It ran like a bat out of hell and no issues. Thanks for everyone's help, I couldn't be more pleased. I started this project 3 months ago with a dead motor that accompanied a cheap jon boat and no knowledge about outboards whatsoever.

Also, the interior lip on the new prop I purchased is thicker than the one that came off my original motor so I'm gonna return it for one with that's the appropriate size.

 

[kbait]

Thanks for your success report!! Nice to see a happy ending.