Merc outboard serial number question

[Pchrispy5]

So I recently got ahold of a 70’s merc 1350 and when I went to look up the serial, it happens to be about 70000 off from the highest that serial set went. A couple other components are odd such as the fuel pump mounted like a side component like they did with the mid 70’s 1150 and 1500 went to rather than the block mounted double pumps. Plan to dig under the cover more today. Is there another way to determine if this is a different engine loaded on a 1350 body other than the serial? Lower does have the double stud through the cav plate that the 1350 would have before the 72-73 switch to single stud. Serial plate doesn’t have engine size on it like my 650 did. Thanks for any help. Still plan to use it, just wanting to know what I have.

 

[Faztbullet]

Its a later model 1974+ 115 with 1350 cowl

 

[Pchrispy5]

I’m guessing a previous owner swapped the block out and kept everything else just off of what I’ve looked up so far. Any pros/cons compared to having the original powerhead? Looks like the carbs may be original. Haven’t pulled it out yet to look at more detail.

 

[Faztbullet]

No just swapped cowlings as the exhaust plate as different and fuel pumps would be on transfer covers

 

[Pchrispy5]

How is the performance between those 2 engines? It will be hooked up to a 2:1 lower unit so I’ll have to make some adjustments on the prop.

 

[Chris1956]

It has the older style starter, like my 1973 850. I did not see the old ugly orange coil, like the '73's had. Does it have the newer black square rectifier or the old rectangular rectifier, with the colored decals?

You might check the block part numbers. That could narrow it down.

 

[merc850]

i think you should rewire it - there seems to be some incorrect connections and corroded wires which can cause a major fire. I am wondering about the connections on the terminal block in image 2 they look like they are coming from the stator but one disappears into the cowling and one is connected to the rectifier; if you are going to check the distributor rotor it doesn't come off - it's molded onto the shaft but you can clean it with emery cloth. It's too bad someone cut the PT hoses they are a vailable online at about $60 ea. Do you have the pump?
I'm posting this wiring diagram as a general guide, if anyone has a more specific one - please post it.

 

[Pchrispy5]

I plan on tearing it down some including a rewire on the whole harness. And new plug wires, clean out the distributor, clean out the starter and replace the contacts. Did it to my 650 as well minus the contact replacement. I haven’t tried turning it yet as I want to try to refresh the rings with some mystery oil first. I was told it was running before it came off the boat. Has just been on a pallet since. Getting it home was the first time it’s been on a stand since it was taken off. They still had a piece of the transom still bolted to the clamps where they cut it from the boat . Assume they wrecked. Here are some other pics as well of the outboard. It’s still put up in a corner as I’m working on my new trailer I’m upgrading to for my boat.

 

[Pchrispy5]

no I don’t have a pump. Would have to buy new.

 

[merc850]

Good that you've worked on one before so you know the plug wires screw into the cap, CDI has the engine harness https://www.cdielectronics.com/product/414-2770/, or Marine Engine.com I bought the last one Mercury had this year

 

[Faztbullet]

2:1 ratio is standard for the I6 motors, the 1350 had 1:78 and the wont see the difference on performance as both where powerhead rated engines. The carbs have the "hump" style bowl covers that only came on early 115 and 150 engine

 

[Pchrispy5]

Any noticeable difference other than the porting to tell the 115 from the 150? Just curious. I’ve only got experience with my ‘68 650 so far.

 

[Chris1956]

The block part number should differentiate a 115HP from the 150HP. I also think the transfer covers are different.

Also, the 150HP motor will have a power port (round hole) in the piston skirt on the transfer cover side. If you pull a transfer cover, you should see the power port.

 

[Faztbullet]

Google search for 852-5264 shows it could be a 1974 150 but could be a 115 also. 1974 115 will not be power ported but some used same casting #

 

[Pchrispy5]

Google search for 852-5264 shows it could be a 1974 150 but could be a 115 also. 1974 115 will not be power ported but some used same casting #

Just got done looking it up and the 5264 block was only used on the 150 in that serial range. The 115 closest matching part number ended in 5254 in that serial range. And the block serial matches the bracket plate serial. Looks like a previous owner was going for the sleeper look lol. Thank you everyone for the help. And to think I got this for $200. I’ll make sure she is labeled right with the new decals.

 

[Faztbullet]

Check compression and spark before you do anything as this can get expensive quick

 

[jimmbo]

Speed difference between the 135 and 150 is only 3 more mph, and weaker Hole Shot. The inline 150 was best suited for very light hulls.

 

[racerone]

Tested a 150 Mercury on a light hull once.-----Ran at 57 MPH and boat started to chine walk.----Put the 115 Evinrude back on and boat ran at steady 54 MPH.

 

[jimmbo]

Tested a 150 Mercury on a light hull once.-----Ran at 57 MPH and boat started to chine walk.----Put the 115 Evinrude back on and boat ran at steady 54 MPH.

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.

 

[racerone]

A 1970 Evinrude.--A stock motor.-----Electric shift with a 115 HP emblem on the hood.