Mercury 150 High Altitude Jetting - Maybe...

Joined
Apr 24, 2012
Messages
18
Hello everyone,

Had what I thought was a relatively simple procedure here that is blowing up in my face. Here is my engine:

1998 Mercury 150L (2-Cycle, 6-Cyl, Oil Injected, 3 Carb)
S/N 0G605507

I bought a Seloc manual, and in the manual, it states NOTHING about jetting for high altitude. It doesn't even have a jetting chart. So, I called Mercury. They offered me the Tech Service manual, but when i asked does it have a jetting altitude chart, or even a reference to jetting sized for high altitude, they said... no. I asked, well is there a tech I can speak with about different main jets that are available for that engine? I can figure it out if I at least have all the different size jets, generally speaking 0-2500' = 0.72 2500-5000 = 0.74 and so on... they said... no.

Mercury themselves has now referred me to the carburetor manufacturer for help with jetting sizes for going from 300', to 6000'. I have never had this much trouble with jetting before. Not with my dirtbikes, hell, not even with my old boat. It was a 1981 Bass Tracker with a Merc 40hp and even it came with a jetting chart, I went down to my local shop, had them order the jets, and done. (said local shop can't even seem to find main jets for this engine)

I know it has em guys... the thing has 3 carbs on it.

Am I missing something here, any advice? thanks in advance...
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,347
Re: Mercury 150 High Altitude Jetting - Maybe...

Normally you would change main and backdraft jets for high altitude. I am surprized Merc couldn't/wouldn't help. I will look in my Seloc manual tonight and see if it has them, as it has specs for your motor. I will also look in my old OEM manual, which will have elevation specs for '77-79 150HPV6 Mercs. Let me see what I can find...
 
Joined
Apr 24, 2012
Messages
18
Re: Mercury 150 High Altitude Jetting - Maybe...

Right on, thank you. Yeah, I was really surprised to not find them in my Seloc manual as well. I kept flippin through pages hoping two were stuck together or something.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,347
Re: Mercury 150 High Altitude Jetting - Maybe...

OK, It was you I looked it up for. I responded in your other post. Your serial number suggested a 1996 Merc. Do you know if it is a '98 or a '96?
 
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