7.5 needs help

Joined
Feb 8, 2004
Messages
7
7.5 mercury is not idling at all. i can get it to start but can not accelerate or deccelerate. i have tried messing with the idle adjust screws and they seem to be having no effect either way. It has great spark, and good compression. If i give it gas or lower the throttle it dies. I'm out of ideas here. On a side note, there is a rather large screw on the lower end with the word "flush" right above it. I don't know what this is for, but since it apparently has been removed several times i decided to take it out and see if anything came out of the hole while it was not running. only a tiny amount of water came out and i can see a bunch of white gritty stuff that looks kind of like large peices of sand. Just wondering what this could be, and if there is anything i should do about it. Any help would be appreciated.
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: 7.5 needs help

I would start by rebuilding the carb with a carb kit. Very simple and cheap to do. What year are we talking about and do you have the serial number?
 
Joined
Feb 8, 2004
Messages
7
Re: 7.5 needs help

it's a 77 and i have the serial numbers. I've taken apart the carb three times now, i have not however, put it back together with a carb kit. I've just been reusing the old gaskets but since it seems to be leaking now (could just be my mistake) i'm going to get a kit. I've never seen anything like this before on a carb. I'm used to working on dirt bikes and lawnmowers, there is a tube running inside the carb that when you squeeze the primer bulb, it spits gas out all over the place just behind the choke valve. Most of this gas just falls out of the carb and hits the air filter, or ends up at the bottom of the casing. I don't know if this is supposed to work this way or not, but it seems odd to me. I've also noticed while running the motor in a bucket of water, the water gets incredibally oily fast and large bubbles come up from around the prop even when its in neutral.
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,786
Re: 7.5 needs help

RB's advice to use a kit and set everything back to spec should fix you up.<br /><br />The bubbles from the prop are the exhaust, which exits under water, to keep the noise level down.
 
Joined
Feb 8, 2004
Messages
7
Re: 7.5 needs help

should it also be blowing exhaust out from the top of the lower end? it blows quite a bit of smoke out from the casing there.
 
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