Repower 1977 StarCraft with 140 hp Mercruiser

[Decker83]

I bought the 77 StarCraft SS I/O with a omc white leg of death. I now have a 140 hp mercruiser motor and sterndrive for it.
I need help with the measurement for the front motor mount. I need the distance from the transom to the front mounting wood.
Measuring form below the keyhole to the far side of the wood. Also how high the wood should be from the bottom of the hull to the top of the wood.

I think the motor is a 1985 but I am not sure. I have the motor tag serial # A314590. I can't seam to find any numbers to match.
The transom assembly serial # is A503440 and the drive unit serial # is A319717.
Can anyone help me identify this engine and sterndrive.

Here or some pics of what I have done so far.



This engine and outdrive came from a donor boat I bought to make the swap.

Any help will be greatly appreciated.

 

[chevymaher]

Mine is a 87 four winns 170 horizon. It is a 140 merc alpha 1. It looks exactly to be what you have for a engine.

I went to my notes and I got 39 1/2 inches from the transom to the bulkhead of the engine compartment. The engine mounting wood is 10 inches wide. Butted to the bulkhead. 6 inches deep in the center. Mine had a 1/2 spacer wood on top of that under the motor mount.

Hull depth may be different than yours but It will get you in the ball park. To dial it in I would measure the mounting holes in the bell housing to gimble to the motor mount you have. the centerline of the bolt holes. Make sure that is in the wood. Mine mounts a few inches forward from the rear of the mounting wood.

Hope this helps some.

 

[Scott Danforth]

unfortunately the front mount height will need to be adjusted to your specific hull once you get the motor in. its not uncommon to leave the engine mounts in a repower until you have mounted the motor... then from there, measure what you need and then remove the motor and go back to finish the mounts.

 

[Bondo]

I need help with the measurement for the front motor mount.

Ayuh,.... As Scott says, the method to determine that answer is,.....

Mount the transom assembly,....
Hang the motor on the rear motor mounts, 'n crane on the front of the motor,....
Adjust the front height, til the alignment bar says the motor is in alignment,....
Then build up the front mount(hull side) to where it needs to be, to support the motor's front mount,....

 

[Decker83]

Thanks for the measurements chevymaher..
Thanks also to Scott and Bondo for your help.. I was afraid I needed to reinstall the engine..

I need to buy a alignment tool. Is there a special one for my engine or will any I-mr or alpha 1 work?

Can anyone help with the engine id? I looked at the sticky note and found the charts and I think it's a
I-MR..
What factory engine manual would I need to buy?

 

[Scott Danforth]

any alignment tool will work. they are $30 on ebay. if you look, you can get the alignment tool, the bellows tools, a gimble bearing, and all the bellows and gaskets for about $150

 

[Alumarine]

For the motor I think you need Mercruiser Manual #10 part no. 90-14693.
That covers 1985-1989 I think.
It looks like you have a points distributor so it wouldn't be newer than that.

 

[Decker83]

any alignment tool will work. they are $30 on ebay. if you look, you can get the alignment tool, the bellows tools, a gimble bearing, and all the bellows and gaskets for about $150

Thank you Scott, I did look on ebay this morning. That's what brought up the question..:facepalm:

 

[Decker83]

For the motor I think you need Mercruiser Manual #10 part no. 90-14693.
That covers 1985-1989 I think.
It looks like you have a points distributor so it wouldn't be newer than that.

Thanks marc, It does have a points distributor in it. From my research, I think it is a 1985 engine and stern drive.
I will try and find the Manual you have listed.

 

[Decker83]

I think the motor is a 1985 but I am not sure. I have the motor tag serial # A314590. ​

The transom assembly serial # is A503440 and the drive unit serial # is A319717

I have the motor out of the boat and I'm trying to start it. I have a remote starter switch connected to the large 12 v power
on the starter solenoid and the small post with the yellow/red wire. I have a jumper from the positive post of the battery and to the positive side of the coil.

When I turn the engine over I get no spark from the coil. With this setup shouldn't this bypass the shift interrupter switch and the safety neutral switch?

I removed the wires from both +& - sides of the coil and had continuity to both sides.

I need help with what I should do next..​

 

[muc]

ENG: 0A314590 01409005 MERCRUISER 140

Manufacture Date:

10/09/1984

Warranty Period : 07/16/1985 - 07/16/1986
14693 1 - SERVICE MANUAL #10 GM 4 CYLINDER

DRV: 0A319717 01988015 MERCRUISER MC1 1.98:1

Manufacture Date:

10/19/1984

Warranty Period : 07/16/1985 - 07/16/1986
12934 2 - SERVICE MANUAL #6 R/MR/ALPHA ONE

OTH: 0A503440 00012006 MERCRUISER MC1

Manufacture Date:

05/29/1985

 

[Decker83]

Thanks for your input. I do have the 2 manuals #10 & #6.
I did not have the manufacture dates.

 

[Bondo]

Ayuh,..... Are there points in the distributor,..?? if so, change 'em,.....

 

[Rick Stephens]

Not sure if it helps, but the earliest dimensional drawings that Mercruiser publishes is 1996 on. Here's the one for the '96 3.0L

When I rebuilt my hull to take a V6 instead of the 3.0L I used the drawings and then built a jig to set mount height. Front motor mount height is determined by transom angle. Motor to transom angle is fixed for all Alpha/Bravo engines.

 

[Decker83]

Ayuh,..... Are there points in the distributor,..?? if so, change 'em,.....

Yes it does have the points distributor. Thanks for your input.

 

[Decker83]

Not sure if it helps, but the earliest dimensional drawings that Mercruiser publishes is 1996 on. Here's the one for the '96 3.0L

When I rebuilt my hull to take a V6 instead of the 3.0L I used the drawings and then built a jig to set mount height. Front motor mount height is determined by transom angle. Motor to transom angle is fixed for all Alpha/Bravo engines.

Thank you for the information.. That's a great link.. :thumb:

 

[Decker83]

I went back to read the sticky notes for no spark.. I didn't try to remove the gray wire for the tach on the neg -side of the coil.
Went out in the garage and tried that tonight and I now have spark and the engine turned over and fired for the first time
since I have had it..

I guess I have a short in the gray wire that I need to find and fix..

Thanks again for all of your input..

Stay safe and inside..