Older 25 Johnson...72 I think

[boykinboater]

I bought this boat this summer and have had it out a total of 6 times now. The last two have been the only one with problems.

I decided to take the boat out last week and double check to make sure everything was in working order before going out saturday to put out decoys. Put her in the water she cranked right up and I idled through the no wake zone. Everything was great. When I opened her up to get on plane the RPM's went way up and I was dead in the water. No foward or reverse. I called my mechanic who tells me that he decided to quit working on motors but agreed to listen to my plight and said sounded like a spun hub. So I went to the prop shop immediatly and pulled the prop. Sheer pin was in pieces and I could freely spin hub inside prop. Prop shop man agreed that the hub was bad and replaced.

So Saturday morning take the boat out and I have foward and reverse power and everything seems to be going great. For the 1st 2-300 yards the ditch we are in is small and I think I am bumping the bottom every 5-10 seconds, but when I get to deep water and the big ditch the bumping continues. I sheer another pin and limp back to the ramp bumping all the way.

Now my question. From reading on hear I am guessing I am having a cluth dog problem. Is it normal for a clutch dog to go from good to bad so quickly? My prop shop guy said that he thought the pitch on my prop was causing the hub to slip. Is this possible? I did lose my gear twice during the bumping period (30 minutes or so). Thanks for your help.

 

[freddyray21]

Re: Older 25 Johnson...72 I think

the motor would have nothing to do with a hub spinning, but might have something to do with a broken shear pin. Usually you can feel or hear the clutch dog when it slips in and out of gear. It will make a loud bang. The bumping could be it going in and out.

 

[tashasdaddy]

Re: Older 25 Johnson...72 I think

when a shear pin goes you usually have nothing, no push, and the pin is what connects the prop to the prop shaft for the prop to turn. take it to deeper water, and try it. if it keeps bumping, 99% clutch dog. also if the creek is to shallow to get out without the motor hitting bottom, get an electric troller to get you to decent water.

 

[boykinboater]

Re: Older 25 Johnson...72 I think

When I took the prop off after fix it was obvious it was slipping and sheer pin was bent. This is the reason that the prop shop guy gave for the bumping being a prop problem and not a motor problem. He said that the bumping was due to the sheer pin spinning faster than the motor could spin the prop and the pin was banging in and out of the hub. Does that make sense?

 

[boykinboater]

Re: Older 25 Johnson...72 I think

Is there supposed to be any back and forth movement in the prop with the nut is completely tightened? Sorry if these are stupid questions, on a scale of novice to expert and don't make the scale

 

[tashasdaddy]

Re: Older 25 Johnson...72 I think

in gear there is a little slop. yes.

said that the bumping was due to the sheer pin spinning faster than the motor could spin the prop and the pin was banging in and out of the hub. Does that make sense?

not really. the pin either engages or not. it breaks.

 

[boykinboater]

Re: Older 25 Johnson...72 I think

I was wondering if I needed a washer or something to snug the nut up against the prop...there is enough play in it that I think the sheer pin would be able to disengage...could this be why the pins were bent?

 

[tashasdaddy]

Re: Older 25 Johnson...72 I think

you need the prop nut plastic cover. #2 in diagram. http://shop.evinrude.com/

 

[samo_ott]

Re: Older 25 Johnson...72 I think

He said that the bumping was due to the sheer pin spinning faster than the motor could spin the prop and the pin was banging in and out of the hub. Does that make sense?

Huh? That does not make sense. No wonder he quit working on outboards!!!

Is the prop and nut tight? Does the bumping feel like you hit a log and then it slams back into gear again?

Read this service bulletin that was just posted in another thread.

 

[tashasdaddy]

Re: Older 25 Johnson...72 I think

he sent me a PM, we talked, he had the shear pin, prop, and cotter key only. did not have the plastic cone "prop nut" that the cotter pin goes thru and holds the prop tight to the shear pin. thus the prop would slip back and forth not staying engaged to the shear pin. the guy he took it too i hope never touches another outboard.

 

[samo_ott]

Re: Older 25 Johnson...72 I think

Ugh. It'd be a disaster without the prop nut. Things could really get torn up down there. Even spacing it with washers would help somewhat if no prop nut.

 

[freddyray21]

Re: Older 25 Johnson...72 I think

good call and catch TD

 

[boykinboater]

Re: Older 25 Johnson...72 I think

I had the prop nut...to make a long story short I am convinced that it is a clutch dog problem. Can I repair what I got or do I need to buy new? How much should cost be to replace? FYI motor is a 1974. Thanks for all your help, and sorry TD for not communicating clearly with you it was my fault.