Mercuiser 3.0 litre engine question

[waybel]

Recently picked up a 94 Bowrider with a bad 3.0 litre lx in it cracked block.See an older 140 HP here locally for sale and was wondering if it would fit in my boat.The one for sale is an old(looks like 80's)blue colored 140HP.Did these engines every really change(blocks and heads)?

 

[Bondo]

Re: Mercuiser 3.0 litre engine question

Recently picked up a 94 Bowrider with a bad 3.0 litre lx in it cracked block.See an older 140 HP here locally for sale and was wondering if it would fit in my boat.The one for sale is an old(looks like 80's)blue colored 140HP.Did these engines every really change(blocks and heads)?

Ayuh,.... They haven't changed much in the last 40-odd years,...
But,...
The crankshaft bolt pattern changed 'bout '90 or so, which Could be an issue...

'n a blue motor, woulda been an OMC...

 

[fishrdan]

Re: Mercuiser 3.0 litre engine question

The crankshaft bolt pattern changed 'bout '90 or so, which Could be an issue...

^^^ Agree, that's a major concern. Look to see if the OMC 140 has a 1 piece rear main seal or the 2 piece rear main seal. Your 94 will have a 1 piece rear main seal.

The OMC accessories won't swap direct over to Mercruiser, but you can swap that stuff over from the old engine.

 

[waybel]

Re: Mercuiser 3.0 litre engine question

Ayuh,.... They haven't changed much in the last 40-odd years,...
But,...
The crankshaft bolt pattern changed 'bout '90 or so, which Could be an issue...

'n a blue motor, woulda been an OMC...

Ok thanks guys will get more info.
are the OMC 140 blocks and heads the same as the mercruiser 140 and what could i do about the bolt pattern problem.Will most parts from the mercruiser transfer over to the OMC?Does it have to be a 1 part seal to work.?

 

[Bondo]

Re: Mercuiser 3.0 litre engine question

Ok thanks guys will get more info.
are the OMC 140 blocks and heads the same as the mercruiser 140 and what could i do about the bolt pattern problem.Will most parts from the mercruiser transfer over to the OMC?Does it have to be a 1 part seal to work.?

Ayuh,.... All of the 3.0l boat motors are a Chevy motor, with accessories from Merc or OMC or Volvo bolted onto 'em....
The "Long Blocks" are the same,...

If ya have both flywheels, the crank bolt pattern can be overcome...

'n, Yep, ya gotta switch all of the parts from 1 motor to the other,...
OMC accessories don't play well with Mercs... or vice versa....

 

[fishrdan]

Re: Mercuiser 3.0 litre engine question

If ya have both flywheels, the crank bolt pattern can be overcome...

I think there's a gotcha' to that, as in there's a difference in the between crank bolt patterns. Bolt pattern diameter is slightly larger or 1 bolt is clocked off a bit,,, or something like that. I had both of them side-side and remember something was different on how the flywheel mounted to the crank.

Maybe someone who has done the swap can confirm of if I'm right or wrong on this as it's been 3-4 years since I looked at the cranks and flywheels.

 

[Bondo]

Re: Mercuiser 3.0 litre engine question

I think there's a gotcha' to that, as in there's a difference in the between crank bolt patterns. Bolt pattern diameter is slightly larger or 1 bolt is clocked off a bit,,, or something like that. I had both of them side-side and remember something was different on how the flywheel mounted to the crank.

Maybe someone who has done the swap can confirm of if I'm right or wrong on this as it's been 3-4 years since I looked at the cranks and flywheels.

Ayuh,... Which is why I said ya need the flywheel, from/ for the new motor...

The old motor is, I believe 3, 1/4", 'n the newer is 3" bolt patterns..

So long as the Op has the flywheel on the new motor, a coupler can be bought to make things fit...

 

[fishrdan]

Re: Mercuiser 3.0 litre engine question

Ayuh,... Which is why I said ya need the flywheel, from/ for the new motor...

The old motor is, I believe 3, 1/4", 'n the newer is 3" bolt patterns..

So long as the Op has the flywheel on the new motor, a coupler can be bought to make things fit...

There's the 12 3/4" and 14" flywheel diameter to deal with also. If the bad 3.0LX engine has a 14" flywheel, it won't work with older engines, not enough room in the bell housing.

For the OP, I would pull the old 3.0 to see how the flywheel, coupler and starter are configured, then compare it to the OMC 140. See if they have the same diameter flywheel, if the coupler will bolt up, starter. I think you'll be safe between the 3.0LX and OMC140 head being the same or close enough, but be aware that there have been 6-7 different heads used on GM 4cyl marine engines through out the years. Who knows what has been done to your 3.0LX or the OMC 140 over the years........

 

[waybel]

Re: Mercuiser 3.0 litre engine question

There's the 12 3/4" and 14" flywheel diameter to deal with also. If the bad 3.0LX engine has a 14" flywheel, it won't work with older engines, not enough room in the bell housing.

For the OP, I would pull the old 3.0 to see how the flywheel, coupler and starter are configured, then compare it to the OMC 140. See if they have the same diameter flywheel, if the coupler will bolt up, starter. I think you'll be safe between the 3.0LX and OMC140 head being the same or close enough, but be aware that there have been 6-7 different heads used on GM 4cyl marine engines through out the years. Who knows what has been done to your 3.0LX or the OMC 140 over the years........

Ok thanks for all the info guys.Will look into it.Sounds like it might be better to find an old or newer 3.0 litre Mercruiser instead.

 

[Bondo]

Re: Mercuiser 3.0 litre engine question

Ok thanks for all the info guys.Will look into it.Sounds like it might be better to find an old or newer 3.0 litre Mercruiser instead.

Ayuh,... Like I said above, the color of the paint is irrelevant...