25 hp Mercury - sheared pin or not? Hard to change??

[kellerqx]

Today after launching my boat and starting it a couple times at the ramp, it would not go. Only the RPMs would increased as I turned the handle, both fwd. and rev. There were no concerns with its ablility to stay started or idle. Once reloaded onto the trailer I inspected the prop and found it would move CW and CCW easily by hand. I dont know if this is normal or not, just an observation. There was no damage to the prop. Only damage was to the cast aluminum upside down fin above it. It was cracked and in two pcs. I dont know if I hit something during launch, but I have ordered another. I picked up a shear pin from the marina. I have never change a shear pin, is it an easy change? How is it done? Are there any online guides? I think I should be able to change it, the guy at the marina says it's easy. Please advise.

 

[JB]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

Since we don't know the year of your engine we cannot say with certainty whether it has a shear pin or rubber hub in the prop.

If it has a shear pin: Remove the nut on the end of the prop shaft. This may involve removing a cotter pin first.

Slide the prop off the shaft. Replace the broken pin parts with the new pin.

Re-assemble.

Go boating.

 

[ThumbPkr]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

I looked at his old posts to find mention of a mid nineties 25 horse Mercury.
Since Mercury pioneered the rubber hub in the prop to eliminate the shear pin back in the mid fifties it puzzles me that they might have gone backwards to a shear pin again but Mercury today is not what I grew up with so anything is possible I suppose.The parts man played along with him in any case.
I would be interested in finding out the answer myself.Ron G

 

[kellerqx]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

Yes it is a 1996 model, thanks for the info. I will post my results from the tear down. I should be able to get to it this weekend some time.

 

[OldMercsRule]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

I have a 1996 Merc 25 and it has a rubber hub, (on the prop shaft).

It may have a shear pin on the flywheel, (but that would be another kettle of fish), and a different diagnosis fer a different type of problem.

This particular Merc 25 musta been built on Mars or some such. JR

 

[OldMercsRule]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

Sorry fer bein' such a smart arse, the Martians would be lucky ta have such a fine engine.

Here is what I would do if the engine were mine.

Carfully look at the prop and see if you can find the Merc part # to cornfirm the prop is the standard issue fer the 25 hp two stroke, (which it prolly is).

Check on iboats what a new prop would cost, (same exact wheel as you have).

Take the nut off and pull yer prop off the engine n' take it to a "prop shop". (Metro Seattle has shops like this), so if you live in a large Metro area you will also have propeller shops.

With the knowledge of what a brand new prop from iboats costs ask them fer an extimate to re hub and fix dings you have (if any). If the price is right do it; if not go back to iboats or try ebay for a used wheel.

Put a little grease on the rebuilt wheel, (on the prop shaft when you get her back fromn the "prop shop"), tighten down the nut n' BOOM.

Proplem solved.

Hope that helps. JR

 

[kellerqx]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

Thanks for the added information. I will try to remove the prop and follow your direction, luckily the seller gave me an extra prop when he sold it to me.

To me the prop feels attached to the shaft, I cant visually see any slippage around the nut and shaft. To me it just feels like the prop and shaft are rotating freely. As well as it wasnt having that pre engagement grind sound before going into gear. It only revs. up and down ( fwd and rev. ).

 

[OldMercsRule]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

Thanks for the added information. I will try to remove the prop and follow your direction, luckily the seller gave me an extra prop when he sold it to me.

Ahhhhhhh..... an easy solution. Put the spare prop on.

To me the prop feels attached to the shaft, I cant visually see any slippage around the nut and shaft.

Well then let's propose a solution: shall we?


To me it just feels like the prop and shaft are rotating freely. As well as it wasnt having that pre engagement grind sound before going into gear. It only revs. up and down ( fwd and rev. ).

Laddies or one of the truly "big guns" on this forum devised a way to tell if the hub is slipping. Very simple. Get a marker, wax pencil et al or something that can mark both the rubber hub and the aluminum propeller. Mark both in such a way that you can tell if the allignment changes. Put her in the water n' start her and see if it slips. I hope it does as that will be the least expensive fix fer you since you already have a spare prop.

If the engine still revs up and the prop doesn't slip then yer problems are a bit bigger. I mention this as you claimed there was a 'feel' like the unit was not shifting into gear which is possible as well. I own an early 1980's 25 Merc, (as well as me 1996 that is identical to yers). The early eighties Merc had a plastic holder break in the cable linkage that would not allow it to shift and it stayed in neutral.

It was easy to fix but you need to find one of those plastic parts for the linkage, (which I had to order), as none of the dealers had 'em nearby.

If the prop doesn't spin (verifying the proplem with the two marks you made), then pop off the hood and carefully observe the cable shift linkage to make sure it is shifinig into gear. You can do this in the water or on the trailer as when it shifts into gear the propeller will not spin freely (as it does in neutral).

One final thing: make sure yer 12 year old sees you take the shear pin back to the place that sold it to you to get yer money back and let them know that was not apreaciated, as it led to a cornsiderable waste of time. They should have known better.

Good luck. JR

 

[kellerqx]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

Thanks for the advice, after further investigation the root cause was found to be the shift linkage. Specifically the plastic socket was broken and fell off the ball. Unfortunately I cant buy just the plastic socket, I have to buy the kit and it will cost $23. Guess thats cheaper than a service fee. Thanks again.

 

[OldMercsRule]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

Thanks for the advice, after further investigation the root cause was found to be the shift linkage. Specifically the plastic socket was broken and fell off the ball. Unfortunately I cant buy just the plastic socket, I have to buy the kit and it will cost $23. Guess thats cheaper than a service fee. Thanks again.

You definately CAN buy the plastic socket, (I did it), and it was a cheap fix, that is why I mentioned the possibility as that is the same problem I had on my 25 Merc in the post above ^^^^.

Shop at the inline places that have the complete parts pull down menu, (try the first post in this section fer starters). I forgot where I found it but there was more then one place that sold just the plastic socket fer the linkage.

You may face a minimum charge on yer order so try to get the order up as high in usable cornsumable parts like water pump parts, spark plugs et al when ya place the order.

Good luck, JR

 

[ThumbPkr]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

Glad you got a handle on it.I wonder where the shear pin went?Can you get a refund on it?Ron G

 

[kellerqx]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

I should have control, as soon as the kit comes in. Five minutes and I am back on the water. I cant find just the plastice linkage, I was told I could. Guess I am not finding the right website. I have seen several like it, but from the parts book it doesnt give an individual part number. So I guess at this time I will just have to pay for the kit. As far as the pin, returned it for credit.

 

[OldMercsRule]

Re: 25 hp Mercury - sheared pin or not? Hard to change??

2 minutes and I found it.

Part # 98465 superseded to 19384 "Socket ball @ $6.54

The online site cornpetes with iboats so I can't linc it but any site with an online parts catelog fer yer 25 hp Merc, (prolly 10 of them out there or more) will have this item at a similar price.

The min charge could make the price as high as the "kit" you bought, and I didn't look at that.

JR