50 Years!

[Big Jay]

Hi guys, just wanted to share something here that I've found. Sometimes the ghost in the engine is real!!

I can't help but wonder how many owners, mechanics and backyard tinkerers over the last 50 years have been stumped on this engine.. or worked on it and missed it!

1969 Merc 1000 Tower of Power, serial 2685637. Bought it with an old 16ft glass Crestliner this spring, couldn't get over 4k RPM at WOT and had a rough idle. So I decided to tear it apart and install some carb kits and rebuild the fuel pumps in an attempt to right it.

First carb went as expected, then came the second (middle) carb. I disassembled and soaked it in carb cleaner before wiping it down and blowing it out to inspect for damage and wear. I held it to the light and peered through idle adjust passage (screw removed) and saw "way" too much light shining through back at me.

So I turned the carb around and there is a hole about a 16th of an inch in diameter in the body! Right where the low speed connects to the welch plug chamber. I can only assume it's a factory defect, or maybe a disgruntled mechanic haha... (it's a pretty round hole, maybe drilled?)

I doubt it's the reason for my WOT low RPM issue, but I bet it'll go a long way to smoothing my idle issues!!


Hahaha!

 

[jimmbo]

The other two carbs have either no hole, or it is plugged?

 

[Big Jay]

No, I also have a parts engine and none of the carbs (on either engine) have this hole. I plan on swapping the carb out with another and will hope for some change I guess..

 

[Big Jay]

You know, I've found myself wondering over the last few days haha.. is there any legitimate reason someone would've purposefully drilled that hole into the carb? Maybe to enrich the fuel flow on the cylinders 3 and 4 for some reason?

 

[Texasmark]

How about a casting defect...It happens.

 

[Big Jay]

Hi TexasMark, thanks for the reply.

Not a newbie by any means.. been boating all my life, and working on outboards for a number of years (at-home-tinkerer). But coming across a perfectly round lone hole along the idle passage in one of three carbs.. can't help wonder if it was put there for a reason. I have an identical parts engine and upon checking, there is no hole on any of its carbs (I've since swapped out the one with the hole in it for one without, just finishing the fuel pump kits and installing new fuel lines before trying it out).

My original thoughts were of a factory defect, possibly leading to 50 years of misdiagnosis heehee... but then started wondering if someone had had a method to their madness.