Sheer Pin ????

[denniston]

Can anyone tell me where I would find a sheer pin on my 1978 Chrysler Charger? I'm very new to boating and i hit a rock yesterday...I'm afraid i ruined my lower unit or something. The prop spins pretty freely as well as the shaft that with the nut holding it on. IF someone could explain how it works would be great!<br /><br />Thanks!

 

[12Footer]

Re: Sheer Pin ????

I'm afraid you may have a sheared shaft, because the shaft is splined. There is a shear pin of sorts, but it is only used to hold the prop on the shaft. The prop has a standard rubber hub for protection. but seeing how the entire shaft/prop assembly is turning in unison, it might have broken the prop or driveshaft.

 

[eurolarva]

Re: Sheer Pin ????

When you spin the prop does it make a clicking sound? I doubt this happened but you may have busted the shift linkage pin in the rear of the unit and the clutch may be stuck in neutral. This would be a best case senario. What ever the problem is you will need to take the lower unit apart and see what kind of damage has been done. You will need a manual to do this and you will also need to get a seal kit if it can be repaired.<br /><br />Drop the lower unit and remove the water pump. Try turning the driveshaft while it is attached to the lower unit listening for clicking or feeling for resistance. Pull shaft out and check splines on both ends to see if they are damaged. When you get it apart post here and tell us what you see. If the damage is minimal hopefully you can fix it and use it again in a couple of weeks. <br /><br />Keep an eye on ebay for lower units that will work on your motor. I bought one this winter that I am now using on my boat for 36 bucks.<br /><br />Also post your model number on your motor here and I will keep an eye out on ebay to help you find a lower unit.<br /><br />Good Luck

 

[denniston]

Re: Sheer Pin ????

I'm encouraged that you found a lower unit for 36 bucks. I have a manual, and have replaced the impeller last fall, so I should be able to manage getting the lower unit off... I started with the prop this time??? I was thinking that the prop shaft would come out that way...I shifted in to forward, and the prop shaft spins freely with no grinding or clicking?? that's what I know now.<br /><br />Model: 1409H8A<br />Serial: 1845<br /><br />I appreciate all you freindly help. <br /><br />p.s. this is my first boat.<br /><br />By the way isn't there any sort of sheer pin or something that should break if you hit a rock...seems like a poor design.

 

[eurolarva]

Re: Sheer Pin ????

I did some checking on your motor and did not realize the size. It looks like a 1978 140HP motor. It looks like most 125 chrysler and force lower units will fit this motor however this is not the 36 dollar unit I mentioned on ebay. I found a couple of force units that are going around 4-500 dollars right now. I agree with you that it sucks that these dont have shear pins that will shear and save the motor. Hopefully when you get this apart the damage will be minimal.

 

[denniston]

Re: Sheer Pin ????

Well I'm kinda confused....I pulled the lower unit off, and I twist the drive shaft, propeller shaft spins smoothly, but when I was in the water the other day I couldn't get the motor to move me??? I'm not sure what's up with this, maybe it's all ok...let's hope.<br /><br />By the way do you think a composite propeller like a Prinanha Propeller would be better for this motor with out the sheer pin.

 

[denniston]

Re: Sheer Pin ????

I think I got it figured out, I was reading some other forums on here, and decided to check out what was going on for some other guys....the prop I have has like a vulcanized gear in the middle, and I beleive that rubber is made to give way, and I think it did yippie for me...now to figure out what to do for a prop...any suggestions...thanks Jason

 

[rickdb1boat]

Re: Sheer Pin ????

Probably spun the prop hub. Take it to a prop shop and have it checked out...

 

[12Footer]

Re: Sheer Pin ????

And it's not a poor design. It's the 'improved' way most l/u's on most motors are now protected. It doesn't allways werk in it's task to save the gearing, but it sure does most of the time. <br />This rubber hub has taken the place of shear pins that older designs used to use. As stated, you still have one, but it holds the prop on the splined propshaft.<br />Your prop can be rehubbed, so don't throw it out. Take it to a prop shop, or a machine shop that can do prop reconditioning, and for 40buks or less, you'll be back in the saddle.