Merc outboard serial number question

[Dukedog]

Curious as to whether the 115 was crank or prop rated?
I know my prop rated 115 Merc was faster than my crank rated 140 Evinrude on the same Hull.

think merc started tha prop rating 'bout '83 maybe '84?.............

 

[jimmbo]

82 was the Year that Merc started Prop Rating, on the engines engines above 70 hp.
OMC switched in 85

 

[Dukedog]

thought it was 'bout tha same time they changed tha block........ whats an OMC?????? (ha)

 

[Pchrispy5]

I noticed the block has an “X” stamped just under the part number on the block, but can only really seem to find reference to the J blocks online. Is there anywhere that has reference to these letter stamps? Wondering what the X stands for and what others there are?

 

[Faztbullet]

Pull a transer port cover as that block casting is used on the non ported 115

 

[samps22]

I noticed the block has an “X” stamped just under the part number on the block,

So does mine.


So, according to an earlier entry in this convo, this number was only used for the 1500 in '74. My motor also has cowling saying '1500' and '150HP', but the previous owner says he bought those to replace the original '1150' and '115HP' ones that were quite deteriorated, I'm now confused, but often happens.

Anyway, I'm 'new here', have never had a boat before. My motor doesn't have a serial number on any bracket, so I'm trying to suss it out by reading hints and tips all over the web. I'm mostly aligned with 1974 being the year of manufacture and 150HP being the yield of the thing. It goes very well, btw. It's got just over 200 hours on the clock, if it is actually the original motor connected with the dash on the boat (which the previous owner reckons it is).

 

[samps22]

Another thing that strikes me, seeing OP's photos of the block of the motor... There is a serial number chiselled into the block where it says: 'SER NO".
No matter how hard I look at mine can I see anything that would even make a dip in the paint in that spot...
Have I bought a counterfeit copy of a 50 year old motor?
;-)

 

[Pchrispy5]

Another thing that strikes me, seeing OP's photos of the block of the motor... There is a serial number chiselled into the block where it says: 'SER NO".
No matter how hard I look at mine can I see anything that would even make a dip in the paint in that spot...
Have I bought a counterfeit copy of a 50 year old motor?
;-)

View attachment 396076

Yours is a replacement block. They won’t have a serial number stamped. Did find something about that on other forum and site searches myself.

 

[Pchrispy5]

Is this what you mean by the power ports? Runners look super clean and piston skirts from what I can see without turning it are also in beautiful shape. The outside of the block is really dirty though whole block is black.

 

[racerone]

Nope--Not the power ports.--Those holes ( circled in red ) must have a nylon insert with a specific hole size.----They are called " bleed inserts " by Mercury.-----I often find 3 of 5 missing.-----I install 8-32 stainless setscrews with correct hole size in them.----Never to go missing again.

 

[jimmbo]

Power Ported Cylinder/Block


Pistons with holes are used with Power Ported Blocks


Non-power Port Cylinder/Block

 

[Pchrispy5]

Nope--Not the power ports.--Those holes ( circled in red ) must have a nylon insert with a specific hole size.----They are called " bleed inserts " by Mercury.-----I often find 3 of 5 missing.-----I install 8-32 stainless setscrews with correct hole size in them.----Never to go missing again.

The sleeves are in the holes. It just wasn’t a great picture

 

[Pchrispy5]

View attachment 396094

Power Ported Cylinder/Block
View attachment 396097

Pistons with holes are used with Power Ported Blocks
View attachment 396096

Non-power Port Cylinder/Block
View attachment 396095

I’ll take a look through the spark plugs. Haven’t refreshed the rings with oil yet so I don’t want to turn it .

 

[racerone]

I usually find 3 of the 5 bleed inserts missing !----But I can not inspect your motor !

 

[Faztbullet]

As I stated its a non ported 115 as you there are no ports in piston

 

[Pchrispy5]

I may be looking for a set anyway as I’m not happy with the cyl 1 piston face. Kinda looks like metal rice melted to the surface on one side, but just carbon and oil buildup on the other. The remaining cylinders just look oil soaked and have carbon buildup. May crack the case due to some very minor surface scratches in the cylinders. Looks like normal wear on the walls, but if I’m rebuilding, then I might as well replace the rings and hone it.

 

[Pchrispy5]

Here is a couple pics from the scope. First is that melted rice section, which is only on the exhaust side and doesn’t seem to have any additional scoring outside of norm. Second is a pic of the intake side. Yes, they are not ported. This side shows how all the others basically look with various patches of clean piston. Is that normal on that cylinder one piston? Making sure the blocks good before pushing too far. It will be a while before I can start tearing it open.

 

[Pchrispy5]

And another loop back on the block, as I only found this block part number under my serial range for the 150 (marineengine.com) would it have the power port cutouts on the block? And would replacing the pistons to the newer ones with power ports allow that feature to work? Sorry to beat a dead horse from a different angle. It’s how I found a device to get my Mercury analog tach to work with one of the rare versions of the 650 without a stator/rectifier (1968). I heard the 150 carbs are ported and I’ll check those part numbers later. Any other differences in passages/parts?

 

[racerone]

Looks like pre-ignition damage on #1 piston.-----Or overheating.----Many of these in line six motor need a new impeller every 3 years or so.----Many do not have an overheat warning horn either.

 

[Pchrispy5]

Looks like pre-ignition damage on #1 piston.-----Or overheating.----Many of these in line six motor need a new impeller every 3 years or so.----Many do not have an overheat warning horn either.

Good thing I make a habit of doing it every 1-2 yrs. Usually annually. Better safe than sorry. And I always look back when I start up the outboard to make sure I got that steady stream going.