# Need motor help.



## bAcKpAiN (Apr 18, 2008)

Yesterday I took a friend and his son out on the river at Trenton for some herring and striper action. Everything is going well, and we are motoring up the river from the Duck Island launch toward the bridges at WOT. All of the sudden my 15HP Mercury seems to throttle up about 2000 more RPMs than normal and we lost almost all power simultaniously. I am thinking that I lost the prop somehow, but upon inspection the prop is attached, and spinning the correct direction with both gears. Just there is no power whatsoever. We barely have enough thrust to fight the weak outgoing tide, almost like I have throttle to a certain point and I start losing traction and the wheels start spinning and the RPMs skyrocket to put it in terms I can convey. It was like trying to drive a car on ice all the way back to the ramp. 

> Motor is a mid 90's 15 HP Mercury Longshaft tiller
> Boat is a 14' V Aluminum with wooden floor.

I am thinking I had too much weight in the thing, there is no way in God's green earth I needed a 35gallon baitwell with three average sized people! But before you totally lynch me the boat is rated for 985lbs cargo. 

I have been told I "spun the prop" and need to take it off and have it looked at. But someone also told me that it could have been from overheating. You guys have any experience in the area? How much am I looking at here?


----------



## Gamefisher (Apr 18, 2008)

Your prop might have a shear pin - they are designed to brake if you hit something to avoid damaging the lower unit or engine. It could have snapped.


----------



## fishook88 (Apr 19, 2008)

After you look at the shear pin like gamefisher suggested I would then move on to the gear box. My only experenice with shear pins are when they break you lose all power from the prop. But I think the shear pin is the place to start.


----------



## bAcKpAiN (Apr 19, 2008)

Took the prop odd and instead of a shearpin it has a rubbery gasket type hub that got spun out. I went to a boat shop and the option was to have the hub rebuilt for 35$ or get a new prop for 50$. The wife was with me and said to get the new one for 50$. I will probably take the old one back later on and get it re-hubbed as a spare. I will let you all know how it works out for me!


On a side note.. How hard it is to change the lower unit oil and replace an impeller? Working on the thing is getting me some bravery.


----------



## Waterwings (Apr 19, 2008)

I've never changed an impeller, but have changed lower unit lube quite a bit. Here's some instructions posted by esquired on April 9th in another topic:

"You can change the lower unit oil by pulling a drain plug letting it run out and refilling - always fill from the bottom. While I am not familiar with your outboard, generally you will see two plugs, one at the top of the lower unit (to check the oil level and let air out as you fill) and one at the bottom (to drain and fill) 

Unbolt the top plug (careful that you do not lose and seals) and then place an oil pan under the bottom - unbolt that plug (again, watch for stuck seals that you might lose). Drain all the old oil out. You them use a pump (sold with the new oil) and fitting to pump in the new oil until it reaches the fill level."


----------



## Popeye (Apr 19, 2008)

Not sure about other brands but my old Honda has crush washers under the plugs. You need to replace these as they are one time use only. You maybe might get away without replacing the crush washers but why risk it?


----------



## bassboy1 (Apr 19, 2008)

I cannot tell you the exact procedure, as you bought a merc, and not a real motor, but replacing the impeller shouldn't be that hard, and won't take much time. But, don't do any work without a service manual. You should still be able to get one of those from a dealer, but I am not sure of that, again, as I only deal in real motors.  
One thing though, I would go ahead and get the whole water pump rebuild kit. It is usually 25 bucks or so, as opposed to 10 for the impeller, but it replaces all the rubber parts in the pump that deteriorate just as fast as the impeller. Also, don't change the LU lube until you do the water pump, as it has to be drained to do the water pump. Pulled that one when I first changed an impeller a few years ago. #-o


----------



## bAcKpAiN (Apr 19, 2008)

Well the "unreal" motor came with the boat silly boy  I am probably just going to get the impeller simply because the full rebuild kit from the store here comes with the pump housing and all sorts of garbage and is 100$ while the impeller itself is $20. I do have a service manual that shows the teardown and rebuild procedure for whole motor (a little more detail than I need but it will work).


----------



## bluegillfisher (Apr 19, 2008)

When I changed out my impeller('89 'rude 25 hp) the impeller came with instructions that were much better than my manual.


----------



## Popeye (Apr 19, 2008)

bassboy1 said:


> ...as you bought a merc, and not a real motor...



Hey, what's the matter with a Merc?


----------



## Captain Ahab (Apr 20, 2008)

It is simple to change the impeller on your merc. I own two merc Optimax 150s and they are real motors - of course these are meant for the Ocean.

Contact these guys they are super helpful (and really know Merc outboards) and will ship all the parts you need.
https://www.franzwarvmarine.com/


----------



## bAcKpAiN (Apr 20, 2008)

I am getting a dead link.


----------



## bassboy1 (Apr 20, 2008)

Parts for those unreal motors sure cost a lot. For a 15 horse Johnnyrude, it is about 10 and 25 respectively. BTW, you know I am just yanking your chain....  

Esquired's link isn't a dead one for me.


----------



## redbug (Apr 20, 2008)

flounderhead59 said:


> bassboy1 said:
> 
> 
> > ...as you bought a merc, and not a real motor...
> ...



nothing wrong with a merc nice motors just like yammies are good motors..
to each his own. I would never buy a rude or johnson I've seen to many of them 
break down for my taste.


----------



## Popeye (Apr 20, 2008)

bassboy1 said:


> ...those unreal motors...



See, I misunderstood you. I didn't realize you were referring to them as Unreal. :lol: :lol: 

I'm gonna stop now so we don't get one of those which is better, Merc vs Rude vs Yammie, Ford vs Chevy vs Dodge, Cats vs Dogs, Spanking vs Getting Spanked debates going.


----------



## bAcKpAiN (Apr 20, 2008)

Link works now.


----------



## bassboy1 (Apr 20, 2008)

flounderhead59 said:


> bassboy1 said:
> 
> 
> > ...those unreal motors...
> ...


Sure left myself open for that one. #-o #-o 

Anyway, I am not trying to hijack your thread anymore than I am, but as soon as I have the time to get my 1936 Evinrude running......

Oh wait, some motor companies weren't even around in 1936. [-X


----------



## Popeye (Apr 21, 2008)

bassboy1 said:


> Oh wait, some motor companies weren't even around in 1936.



Nope, not quite that old. Merc first started building outboards in 1939.


----------

