Outboard unit slams when we put it into gear

rstring1

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Jun 21, 2008
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I have a 1967 Mercury i/o that runs off a Buick v6. Motor runs great, boat looks great, problem is, everytime we put it into gear the entire outboard unit swings clockwise and SLAMS into the boat. The noise is so loud and the force is so powerful it shuts down the boat. I checked to make sure all the shafts are free and there are no major gears damaged, and everything appears alright. Main downshaft turns freely, prop turns freely, what could it possibly be?
 

SpinnerBait_Nut

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Re: Stern unit slams when we put it into gear

Re: Stern unit slams when we put it into gear

Mercruiser, OMC, Volvo & other I/O & Inboard Engines & Outdrives
 

Don S

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Re: Stern unit slams when we put it into gear

Re: Stern unit slams when we put it into gear

everytime we put it into gear the entire outboard unit swings clockwise and SLAMS into the boat.

I may not understand what you are saying is happening, but have you tried holding onto the steering wheel?
 

jerryjerry05

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Re: Stern unit slams when we put it into gear

Re: Stern unit slams when we put it into gear

Take a couple of pics and post .Off hand if the unit is moving like you said it did then the steering gimbal may need washer /replaced,it's broken???
Step back ther and grab it and try to move it by hand or a big pry-bar.Jerry
 

CharlieB

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Re: Stern unit slams when we put it into gear

Re: Stern unit slams when we put it into gear

You said that the vertical shaft spins freely, have you had the lower unit off and checked?

Pull the lower unit off and check again, this time shift it into gear, can you still turn the vertical shaft?
 

EarlyWood

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Re: Stern unit slams when we put it into gear

Re: Stern unit slams when we put it into gear

I may not understand what you are saying is happening, but have you tried holding onto the steering wheel?

I am only a cadet, but am raising my hand to say I had the same thought...ya know what they say about great minds...they say something
 

rstring1

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Re: Stern unit slams when we put it into gear

Re: Stern unit slams when we put it into gear

I forgot a few things; it has electric shift, and the force is so great that if we hold onto the steering wheel, it will break your arm. I did take off the lower unit, all spins freely. On the upper unit, I took off the top piece and there appears to be some sort of worm gear missing. I will get pics and post.
 

bomar76

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Jun 27, 2002
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Re: Outboard unit slams when we put it into gear

You said in post #1:
"I have a 1967 Mercury i/o that runs off a Buick v6"
Then in post #7 you say:
"it has electric shift"

Here is some news.....There are no Merc electric shift I/O's...and there are no "worm gears" in Merc outdrives either.

based on the little information and misinformation you have posted I'll take a WAG and conclude you have an OMC outdrive.
 

Don S

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Re: Stern unit slams when we put it into gear

Re: Stern unit slams when we put it into gear

What drive do you have?? Are you sure about the year??? In 1967, there weren't any V6 engines, and I don't know of any electric shift Mercruisers.
I would suggest (as jerryjerry did) that you post some pictures so we can get some things identified.
 

rstring1

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Re: Outboard unit slams when we put it into gear

Hey guys, I'm new at this. Here is a pic of the boat. The registration states it is a '67. The motor IS a Buick v6.
attachment.php


Here you can see the damage to the outboard unit, note the crack;
http://forums.iboats.com/attachment.php?attachmentid=14094&stc=1&d=1214163908

Let me post this and see if it works. More pictures to come.
 

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Don S

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Re: Outboard unit slams when we put it into gear

I have a 1967 Mercury i/o that runs off a Buick v6.

Not sure how you expect anyone to see anything on a picture that is only one inch spuare, but I seen enough to know that it's an old OMC stringer drive and has nothing what-so-ever to do with Mercury (Mercruiser)
FYI: Mercury is outboards, Mercruiser is what the I/O's are called. Both are a part of Mercury Marine Corp.
 

rstring1

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Re: Outboard unit slams when we put it into gear

Okay, sorry about the pic sizes. Like I said, i'm new at this and I can't seem to get the pictures to cooperate either. Here are the pics, hopefully better. Note in the third pic I put an arrow in, is there supposed to be a "dampening gear" or a worm gear in this location? Please, all help is very much appreciated.
 

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RJLeuwen

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Jun 19, 2008
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Re: Outboard unit slams when we put it into gear

No. Because the steering cable comes thru the transom and attaches externally to the drive. If it had internal steering then there would be 2 gears in that location.

RJ
 

kd7isf

Petty Officer 2nd Class
Joined
Aug 20, 2004
Messages
162
Re: Outboard unit slams when we put it into gear

I disagree.

I have a 2.5l OMC Stringer and it DOES have a WORM GEAR in that location. Said worm gear is on a shaft that protrudes next to the ball gear and meshes with a small gear on the intermediate unit (the part that sticks through the transom).

Don't bother looking for it though -- that worm gear IS there, but you'll never see it from the top.

AND your problem is NOT in the steering YET.

DO NOT PUT YOUR BOAT IN GEAR WHILE THE ENGINE IS RUNNING -- Until you read the rest of this post and follow the provided instuctions. You can easily turn this $3 - $5 problem into a $3000 - $5000 problem in just seconds.

Yes, you can really fix this properly for about $3-$5 and about 2hrs of simple handiwork.

Please do the following and let me know the results.

Have one person stand near the back of the boat (in view of the prop, but safely away from it).

Have a second person get in the boat.

Person in the boat removes the coil wire (spark wire from the coil to the middle of the distributor). This step is not neccessary but can prevent serious accidental injury.

Person in the boat then verifies the ignition is OFF.

Person outside the boat tries to turn the prop. It should turn freely. (98% chance it does)

Person inside the boat turns the ignition to ON or RUN (same thing) but DO NOT TURN IT TO START!

Person outside the boat tries to turn the prop again. Since you said there was no problem until you tried to put it in gear, I'd say the prop should still turn freely at this point.

Now, the person in the boat puts the boat in gear (DO NOT START THE ENGINE!! The ignition should still be in ON or RUN).

Now the person outside the boat tries to turn the prop again. If all has been good up to this point, I'd say you have a 99.95% chance of NOT being able to turn the prop at all.

Don't worry. This is actually a good sign. It means the expensive parts work!

You said you have electric shift. If my guesses above were right, you have a very easy to fix problem. -- Both of your clutches (FWD and REV) are engageing at the same time. This binds up the drive and prevents the shafts from turning. The force required to stop a running engine is incredible -- and why your drive is acting like it is.

The good news is, you probably just need to fix some wireing. (Yup, your problem is just a dumb wire).

Want proof?

Leave the boat in gear and turn off the ignition.

You can now turn the prop freely.

Reply to this forum if my guesses and suggestions above were correct and i'll give you step by step directions on how to fix this.

Hope this helps
 

chiefalen

Captain
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May 18, 2008
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3,598
Re: Outboard unit slams when we put it into gear

You have a manual for that drive set up?

Omc original the best seloc second best.

Would you please post a picture of the entire out drive including the transom starboard side.

Right side.
 

Don S

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Re: Outboard unit slams when we put it into gear

Old thread guys...................
 
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