The MV ScubaBoard...

[The Chairman]

Well, I think that I have a 3.0 liter OMC engine, Its carb is on the port side. The block number is 2770087. I have been unsuccessful in trying to positively ID it so far.

 

[The Chairman]

Yesterday, I started to figure out the engine control. It says Morse in the front and has one lever with two buttons. Two cables come in to the back. One goes to the throttle lever and the other to the transmission. The lever started out as being stuck. Removing the trans cable resolved that, and it moves, albeit a bit stiffly. You can feel a spring loaded detente in the middle. From here moving it forwards or backwards increases the throttle. The button on the side engages the lever for the trans cable and it moves forward or backwards with the lever. I can't get the forward button to move at all.

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Also, as I mentioned in the previous post, I don't think this is an Iron Duke. If I remember right, those were cross aspirated, with the intake on the starboard and exhaust on the port. This engine has both intake and exhaust on the port side. There is also an side access panel on the starboard side of the block. It has the serial number 2770087 stamped on it. I Googled that and did not come up with a clear indication, but it looks like it might be a 3.0L engine.

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[Cave Diver]

Trying to identify engine and get manual

Casting # could be either engine. Quick way to tell:

Just look at the crankshaft pulley...
If it's the 2.5l, it's Just a Pulley...
If it's a 3.0l,.. There's the Pulley,+ a Harmonic Balancer..."

Might read this also: http://forums.iboats.com/showthread.php?t=381208

 

[captain]

It looks to be the 4 cylinder 153 cu/in Chevy II engine. Both OMC and Mercruier used them. The Pontiac Iron Duke came out in 1977 so it wouldn't be in 1968 boat. I have rebuilt 3 of them over the years.

 

[The Chairman]

How do you differentiate between the 2.5L and the 3.0L? Apparently, they had the same casting on the block. I could pop the head and measure the bore (3.875 as opposed to 4.0), but I don't want to do that (yet).

BTW, this has TWO fuel tanks in it. One is plastic (smallish 10 gallons) and the other is built in. Actually, I haven't seen it, but it looks like it should be BIGGER.

 

[Cave Diver]

How do you differentiate between the 2.5L and the 3.0L? Apparently, they had the same casting on the block. I could pop the head and measure the bore (3.875 as opposed to 4.0), but I don't want to do that (yet).

Read my previous post.

 

[Cave Diver]

How do you differentiate between the 2.5L and the 3.0L? Apparently, they had the same casting on the block. I could pop the head and measure the bore (3.875 as opposed to 4.0), but I don't want to do that (yet).

BTW, if you really want to know without popping the heads, you could pop a spark plug out, place a piston at BDC, fill the cylinder with oil and see how much it takes. Compare the volume of oil with the volume of the cylinder for a given bore/stroke and you should have your answer.

 

[The Chairman]

I did... I don't know if I completely trust the source. Not YOU, but the person you quoted. Yes, I could measure volume, but I really want to be able to discern it from external appearances.

I also need to figure out how to change the oil as well. I don't trust oil this old.

Read my previous post.

 

[Cave Diver]

As far as I can tell, that's probably as close as you're going to get with just a casting number. Many of the GM V engines had numbers stamped on a pad, usually on the front of an engine close to the water pump that corresponded with a VIN or serial number. Not sure about the inline engines, or the marine variants, but you might want to look and see. The pad was cast into the block, but had a flat machined surface with stamped numbers and may be covered with gunk.

 

[The Chairman]

FWIW, it definitely has a harmonic balancer on it.