OMC 140 3.0l drive compatibility

[M0bi0us0ne]

Hi, I have an old 1979 OMC 140 hp 3.0L on my boat; aside from the carburetor needing to be rebuilt the engine it's in ok shape. What it is not is the Stringer 400 drive that has been the bane of my existence. I live in Europe where parts are almost nonexistent forcing me to buy highly used parts from the USA for ridiculous money. Does anyone know if that engine is compatible with the Mercruiser Alpha One? Does anyone have any other idea for a drive that would work with that engine?
Thanks

 

[matt167]

Due to the very large hole in the transom for the OMC. It will take a transom rebuild which is a bit of effort and coin as well.

 

[M0bi0us0ne]

Due to the very large hole in the transom for the OMC. It will take a transom rebuild, which is a bit of effort and coin as well.

That is okay. I’d rather do that than keep spending 500$+shipping+import taxes for junkyard quality parts that last one or two seasons before giving up the ghost. But before pulling the trigger on such a project I want to be sure the engine and drive are compatible

 

[matt167]

You would be better served with a complete mercruiser setup. The 140 is the same but you will need a 1.98 drive and an exhaust manifold and all the little parts

 

[Bondo]

That is okay. I’d rather do that than keep spending 500$+shipping+import taxes for junkyard quality parts that last one or two seasons before giving up the ghost. But before pulling the trigger on such a project I want to be sure the engine and drive are compatible

Ayuh,..... Sell the OMC stuff, 'n buy yerself a complete running Merc or Volvo in a rotten hull, then swap the entire driveline, pulleys to prop, into yer hull,.....

The only thing that OMC has in common with either a Merc or Volvo is the motor's Long Block,......

 

[Scott Danforth]

Being a 1979, you need a 1978-1980 stringer drive. The 1977 and older are different, the 1981-1985 are different

And no, the only thing common between an OMC Stringer 400/3.0 and a Mercruiser alpha 1 /3.0 would be the block, head, and rotating assembly. Everything else bolted to the motor must be swapped. Everything.

If you want to switch to a Mercruiser and Alpha drive. You need a complete pulley to prop longtail with all wiring and controls. You will also need to redo your transom, stringers, and engine mounts as well as your dash/gauges

It would be cheaper to part out your current boat and buy a different one

 

[M0bi0us0ne]

Being a 1979, you need a 1978-1980 stringer drive. The 1977 and older are different, the 1981-1985 are different

And no, the only thing common between an OMC Stringer 400/3.0 and a Mercruiser alpha 1 /3.0 would be the block, head, and rotating assembly. Everything else bolted to the motor must be swapped. Everything.

If you want to switch to a Mercruiser and Alpha drive. You need a complete pulley to prop longtail with all wiring and controls. You will also need to redo your transom, stringers, and engine mounts as well as your dash/gauges

It would be cheaper to part out your current boat and buy a different one

Yeah I figured that, I got quoted a minimum of €25k for a completely new set up. I have been able to find used Merc engines and drives for between 5 and 10k but will still need to redo the transom

 

[Scott Danforth]

remember, you will need everything. not just the engine and drive, however the mounts, exhaust, steering, harness, gauges, controls, control cables

if you want to transplant into your boat, get the whole boat the motor and drive is in. you will need it. you will then dispose of what remains.

 

[M0bi0us0ne]

remember, you will need everything. not just the engine and drive, however the mounts, exhaust, steering, harness, gauges, controls, control cables

if you want to transplant into your boat, get the whole boat the motor and drive is in. you will need it. you will then dispose of what remains.

Is there no way to keep the original gauges? It is an old wooden boat, and I would like to keep it as close to original as possible, at least on the surface. New gauges would stick out like a sore thumb.

 

[ScottinAZ]

Is there no way to keep the original gauges? It is an old wooden boat, and I would like to keep it as close to original as possible, at least on the surface. New gauges would stick out like a sore thumb.

keeping the original gauges is going to depend on whether you can wire in the senders on the new motor to the gauges. If they are not compatible, and the old senders from the old motor do not fit (different ports, different threads, etc) then you are stuck with new gauges. Some, such as the tach may not work anyways, as the ignition systems are likely to be different. If you get lucky and they both run points, then the old should work, if you have electronic ignition, then it gets a bit more complicated.....

short answer, it may be able to be done, but expect to run into issues, and have to do some custom wiring to get them to work.

 

[Scott Danforth]

Is there no way to keep the original gauges? It is an old wooden boat, and I would like to keep it as close to original as possible, at least on the surface. New gauges would stick out like a sore thumb.

trim gauge is different range / style / signal

you no longer have tilt up/down with mercruiser

you could get the other senders and tach to work with some effort. however you will need to rewire everything

You can get brand new gauges that look like they were made in 1907 if you wanted.

Steering cable is different, control binnacle and cables are different from OMC to anything else.

 

[M0bi0us0ne]

trim gauge is different range / style / signal

you no longer have tilt up/down with mercruiser

you could get the other senders and tach to work with some effort. however you will need to rewire everything

You can get brand new gauges that look like they were made in 1907 if you wanted.

Steering cable is different, control binnacle and cables are different from OMC to anything else.

I don't have a trim gauge; the 400 can only work trimmed all the way down. I only bring it up when I need to take the boat out of the water. I have an ammeter, oil pressure, temp, fuel, rev counter.

 

[Bondo]

Is there no way to keep the original gauges? It is an old wooden boat, and I would like to keep it as close to original as possible, at least on the surface. New gauges would stick out like a sore thumb.

Ayuh,..... The gauges won't care who's motor is back there,.....

 

[Scott Danforth]

I don't have a trim gauge; the 400 can only work trimmed all the way down. I only bring it up when I need to take the boat out of the water. I have an ammeter, oil pressure, temp, fuel, rev counter.

then you dont have power trim. just tilt.