Extending 150 Mercury

[Themanofsteel]

I came into a 1983 Mercury 150hp outboard with a 20” drive shaft housing. Serial 6366905. I need to extend to 25” to fit my boat.

It seems there was no extension kit for it so I bought the extra long housing for the XL version on this engine but there’s a few small differences...

1. In the pic, the red circle. My current housing doesn’t have that rubber exhaust tube.

2. The green circle, mine doesn’t have that cut in the exhaust port. It's closed like the adjacent port.

3. The blue circle, mine are open and water flows out of there when running. the XL housing, they are sealed.

Now, I can open up those those holes circled in blue by cutting away the aluminum and I suppose the rubber hose can just be removed and the round hole plugged.

I just concerned about that cut in the right exhaust port circled in green. Since my current housing port doesn't have that cut in it, will that be a problem? The second photo shows the cut better.

 

[Themanofsteel]

Driveshaft switch out 20” to 25”

I have a 1983 Mercury outboard 150 hp. Serial 6366905. I need to switch out the 20” driveshaft with a 25” shaft.

Someone told me I’ll need to Shim it and that that is very difficult. Is that the case? What exactly is shimming. How difficult a job is this.

 

[racerone]

Is that a picture of the driveshaft or propshaft ?

 

[GA_Boater]

Is that a picture of the driveshaft or propshaft ?

Prop shaft.

Lets keep these together. The 20-25" extension question comes up often enough that having one thread will make it easier to get advice and for those following along.

 

[Faztbullet]

First you need to measure from the top motor mount to lower mount as yokes are different between a single ram and 3 ram trim. The housing may not mount up. Second is finding a 25" pre-load driveshaft and if you do yes you will need to reshim it. Also need longer water tube and shift shaft. Check before spending any more $$$. Bay MFG makes a 5" kit for your motor...

125 4 cyl.	D283222 and up	414	5 inches
150 V-6 20"	4868998 and up	611	5 inches
150 V-6 25"	6042946 and up	611A	5 inches
150 V-6 20"	6443213 and up	611	5 inches

http://www.baymfg.com/kits/mercury/

 

[Themanofsteel]

Faztbullet What is a extension kit? Where can I buy. I have the longer water tube & shift shaft.

 

[Faztbullet]

Go to the link in my post for bay manufacturing

 

[Themanofsteel]

Looks like the part I need will take 3 weeks to get from Bay Mfg. Does anyone know someplace else I could possibly buy the part. It’s the 611A - 25” extension. I actually only need the driveshaft extension. Not the whole kit.

 

[Themanofsteel]

Question, what purpose does the attached pic serve. It doesn’t seem to hold anything secure. It loosely sits there.

im asking because I bought a extended driveshaft housing and it doesn’t have a place for this part. My shorter housing had this on there.

 

[Faztbullet]

It sets above bottom yoke and keep the motor from coming in boat on a severe impact. Will the newer mid bolt up??? It going to be hard to find a 25" pre-load driveshaft. Call Bay and see if they will just sell the driveshaft extension if every thing bolts up.

 

[Themanofsteel]

The newer X-Long Mid does not have a place for the yoke. Nor did the X-Long engine come with a bottom yoke when I look at the specs. The Long engine did, but the X-Long engine did not.

I called Bay. They said they can sell the 5" extension by itself but it's on backorder for 3 weeks. Was hoping I might find it somewhere else so I wouldn't have to wait that long.

 

[Themanofsteel]

The new mid bolts up to the engine just fine.

 

[Dukedog]

The newer X-Long Mid does not have a place for the yoke. Nor did the X-Long engine come with a bottom yoke when I look at the specs. The Long engine did, but the X-Long engine did not.

all v6 motors have a "yoke".. its tha part on tha bottom of tha steering arm tha lower mounts bolt to.

tha part in your picture is called a "strap".. it went away in later years..

 

[Themanofsteel]

Dukedog ok. I understand now.

 

[Themanofsteel]

Faztbullet I purchased the Extension for my driveshaft from Bay Mfg. Mine has a pin at the top and the extension doesn't. Does the extension need a pin? Also, since mine has that pin it stops the head from setting properly in the extension. See Pics.

 

[Faztbullet]

The extension doesn't need pin. Just set it on top of driveshaft and bolt it up. The pin will compress and add preload to upper bearing just like it was hitting bottom of crankshaft.

 

[Themanofsteel]

Ahh. Ok. Got it. Do you mind explaining preload. For my FYI.

 

[Themanofsteel]

So I was all ready to bolt up the lower and it looks like the fatter part of the extension doesn’t fit through the mid-Section driveshaft hole. It’s about a 1/8” too small. Any suggestions?

The hole is only an opening. If I’m able to clear the hole it should go the rest of the way up no problem.

 

[Dukedog]

guess Faz hasn't seen this yet? ta answer ya question, that pin is spring loaded and when compressed it holds tha top drive shaft bearing in place thus tha resistance when gear case is installed and name "pre load gear case" comes inta play... your extension should do same as direct install inta tha crank and compress tha pin......

 

[Themanofsteel]

So as far as the opening for the driveshaft in the Mid-Section, according to Bay MFG you're suppose to remove the water tube and put the extension though the water tube opening and line it up with the driveshaft opening. Then line up the lower unit driveshaft with the extension.

I could not remove my water tube so I got a long file and filed the driveshaft opening, and made it slightly bigger. The Extension was only about a 1/16" fatter so I only needed to file off a little bit. Worked great!

Finally got it all set. Gonna try it out this weekend.