# 1976 Evinrude 25 hp woes



## Nitrobird (Feb 27, 2010)

Hello to all fellow boaters! This is my first post and I already have a problem lol ! I have a 1976 Evinrude 25 hp (model 25652e) on a 14 foot jon boat and when the boat starts to plane it sounds like the outboard is hitting a stump. What could that be? I have replaced the woodruff key under the flywheel and I replaced the shear pin at the prop. I actually have the outboard running very well other than this problem. Well, while I'm asking questions, does this outboard have some sort of kill switch? Or can I add a modern kill switch?


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## Captain Ahab (Feb 28, 2010)

Welcome


"hitting a stump"??? Do you mean the motor is cutting in and out or that it is actually jumping backwards? If it is cutting out then it sounds like a bad spark check your wires and plugs and replace them.


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## crazymanme2 (Feb 28, 2010)

I have the same motor only in a Johnson.Still hard to figure from your discription.A little more info might help.


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## KMixson (Feb 28, 2010)

Captain Ahab is on to something. I had the same problem with my Evinrude 9.9 once. I would be running and the whole motor would jump like it hit something with the lower unit. It would idle fine. I found out that one of the spark plug wires was grounding out against a line I had installed for a pee hole. My motor didn't have a pee hole so I installed one myself and ran it too close to the wire. After moving the wire away from the line it runs fine now. Check for plug wires rubbing against something as the motor vibrates at speed.


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## Nitrobird (Feb 28, 2010)

Sorry about the vague description, guys. I can tell you that the outboard idles and moves the boat in idle without any hiccups but as soon as I try to get the boat up on plane it feels like the shear pin diameter is too small and the prop spins then catches the pin. If you have ever had a motorcycle with a bad sprocket, that is what it feels like. And the shear pin isn't too small.


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## Nitrobird (Feb 28, 2010)

I will check the plug wires because that sounds similar to what is happening. Thanks guys.


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## Whoopbass (Feb 28, 2010)

Drain your LU fluid and check for metal.
You may have lost some teeth.


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## Nitrobird (Feb 28, 2010)

I actually replaced the gear oil in the lower unit about a week ago and it was dark and thick but contained no metal shavings. I just took the boat out about 30 minutes ago and I am sure the clunking is in the lower unit. :x I guess it's time to buy a service manual and dig into the lower unit....


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## Rat (Mar 1, 2010)

Yes, you can add a modern kill switch to your motor; I just added one to mine, very easy.


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## shizzy77 (Mar 1, 2010)

have you checked the hub on the prop? I have heard of the rubber going bad and the prop spinning on the hub. 

does it shift in and out of gear smoothly?


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## Nitrobird (Mar 1, 2010)

shizzy77 said:


> have you checked the hub on the prop? I have heard of the rubber going bad and the prop spinning on the hub.
> 
> does it shift in and out of gear smoothly?


It does shift in and out of gear fine. I talked to a guy today and his 25 hp Evinrude has the same problem and the outboard shop says it is the clutch. I guess my outboard will be out of commission for a while. Good thing I'm getting a "new to me" 40 lb foot controlled trolling motor for repairing a 55 lb trolling motor for a friend. :mrgreen:


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## underpressure (Mar 2, 2010)

i spun the hub on my prop last year its common and that exactly what it sounds like i have some pics of it if it would help even after i took the prop off it was hard to tell but you will see the melted rubber around the center of the prop


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## Nitrobird (Mar 3, 2010)

underpressure said:


> i spun the hub on my prop last year its common and that exactly what it sounds like i have some pics of it if it would help even after i took the prop off it was hard to tell but you will see the melted rubber around the center of the prop



That would help a lot, underpressure  Thanks for all the suggestions, guys!


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## Quackrstackr (Mar 3, 2010)

I'm betting that you have a spun hub.

The spare prop for my 18 hp Evinrude is the same way from non-use. The rubber has shrunk and hardened. It works fine at idle but as soon as you spin it up, it slips like crazy.


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## Nitrobird (Mar 3, 2010)

What year is your 18 hp?


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## Quackrstackr (Mar 3, 2010)

Old... :lol: 

It's a 68 model.

The prop isn't that old, though. I picked it up for a spare that I never needed until two years ago.. then found out that the rubber hub had gone bad from non-use and sitting in a hot attic and garage.


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## Nitrobird (Mar 3, 2010)

I just pulled my prop and I don't see any rubber in the prop at all. Does any one know of a diagram where I can see where the rubber is suppose to be?


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## Quackrstackr (Mar 3, 2010)

It's underneath the brass that holds / cradles your shear pin. It is a rubber chunk that is press fit between that brash bushing and the aluminum prop cylinder.

https://www.solas.com/products/propeller/ruber_bushing.htm

https://www.mercstuff.com/spunprop.htm


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## Nitrobird (Mar 3, 2010)

I took my prop to the marine shop and it is not the prop....


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## Quackrstackr (Mar 3, 2010)

Ruh roh..... :shock:


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## Nitrobird (Mar 3, 2010)

Quackrstackr said:


> Ruh roh..... :shock:


Lol...has anyone had their gears machined back square. I have one guy telling me that he can machine the surfaces back square and it will work fine. If this is the case, I worked in a machine shop for 13 years and I still know a couple guys that will help out.... :wink:


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## crazymanme2 (Mar 3, 2010)

I never machined them but I have welded them to get rid of the rounded corners & it worked fine.
The only thing I would be concerned with is the extra clearence you will have after it is machined.


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## Macgyver (Apr 6, 2010)

I had the same problem with mine. what is happening is the clutch dog to fwd gear matting surfaces have gotten rounded off. it's jumping in and out of gear. I did a few mods and fixed mine without replacing the gears.


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## lowblazah (Jul 18, 2011)

Macgyver said:


> I had the same problem with mine. what is happening is the clutch dog to fwd gear matting surfaces have gotten rounded off. it's jumping in and out of gear. I did a few mods and fixed mine without replacing the gears.



Mind asking me what mods you did to fix this? I have the same motor and same issue?


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## redrunner (Jul 18, 2011)

Have you checked out the power packs....coils? Same problem on a 78 Evenrude 25. New coil packs fixed the problem. Marine dealer repair man said that I was luck to get 30 plus years out of the junk originals.


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