Outboard Question

[joneshat11]

Last year I would be at full throttle at all of sudden the engine would wined up and lose all of its power, but I would still be able to go about 5 mph. Try to go faster again and all it would do is wined up again. Turn the motor off to duck hunt and the motor would work fine, then about half way back home it would wined up again. It's a 1974 johnson! Some people think it's just prop spin and all I need is a new prop!My father thinks it's more!

What do you guys think? Any help would be great!

[IFallsRon]

Bad gas? Maybe something in the fuel line. I've had trouble with the vent hole on the tank cap. Crack the cap and see if it's a pressure thing.

[Finlander]

I say its the lower unit gears are worn out or the gear dog!
Need to replace the gear dog that keeps the gear in place. Forward or reverse!
Had this happen on my 20 Johnson!
Could this hold true on Joneshat11 motor?

[marine_man]

If it were the dog it wouldn't think (although I've been wrong before) that you'd still be getting 5 mph hour out of it... I think it's an all or nothing type of deal... either the dog is engaged or disengaged, not half ways engaged...

I might believe a slipped prop hub, but it's odd that it only happened a couple of times... and it's somewhat difficult to slip the hub on a smaller hp engine (which I presume it is as you use it duck hunting)... a slipped hub is far more common (although still not a big issue) on larger motors...

It could be weeds... which seems to make the most sense right now.

Have you had the boat out in deeper water?

marine_man

[Fisher Dave]

I dont mean to sound stupid here .. but is the shear pin broken? It could be broken and just barely binding enough to turn the prop under minimal load.. and turn loose under heavy load. I had that happen once.. every other time I had a pin break I had nothing.. this could be your *once*?

Unlikely, but possible.

[Guest]

I'd guess a slipped hub too.

You may be using a small horsepower motor, but most duck boats are loaded down with decoys, ammo, shotguns and dogs.

This happened to me a couple of years ago. Up to a certain RPM I was fine, then it would break loose and spin.

[joneshat11]

Marine_man,

This has happened every time while duck hunting. It just seems that it needs to warm up before slipping! And, Fisher dave your right it started breaking shear pins before this problem and now it just bends them. I'm buying a new prop anyways because of the condition my grandpa left it! I was just wondering if there was more things that could be wrong. Oh, yah its a 25hp!!

[This message has been edited by joneshat11 (edited 02-27-2004).]

[joneshat11]

Thanks everyone for your responses!

[joneshat11]

Last year I would be at full throttle at all of sudden the engine would wined up and lose all of its power, but I would still be able to go about 5 mph. Try to go faster again and all it would do is wined up again. Turn the motor off to duck hunt and the motor would work fine, then about half way back home it would wined up again. It's a 1974 johnson! Some people think it's just prop spin and all I need is a new prop!My father thinks it's more!

What do you guys think? Any help would be great!

[Surface Tension]

I would have guessed the hub or shear pin as well. You said your bending and shearing a lot of pins. Are you hitting the prop that much or is there something else going on? Are you using the original prop nut and are you over tightening it? Finger tight or snug is all you want.

[joneshat11]

Ok guys I got the new prop and it fixed the problem! But of course now there is a new problem. When driving along the river last weekend and engine have kink sound and then the whole engine would shake. This would happen about every 20 seconds while getting up and at full speed! After awhile it would break the shear pin! Any ideas?

P.S. There is a problem that I'm forgetting to tell! My grandfather had this outboard on a runabout where he forgot to release the tension screws on the shifter therefore it stripped the shift lever and I have to use a bungee cord to keep it in forware gear.

[chunkytrout]

Doesn't sound good. Might be time for the shop.

chunk