Harry, when you do your plumbing, you have to decide whether to put the squeezy bulb upstream or downstream of the filter. I chose to have it between the filter and the tank. That way, I can make a little bit of positive pressure to help things along when I drain it. Also, the squeeze bulb doesn't have to deal with a lot of air while I'm first filling the filter. Further, it makes it easy to pressurize the filter to make sure that there are no leaks.

On the other hand, if the squeeze bulb were between the filter and the motor, a collapsed squeeze bulb would indicate a clogged filter.

Anyway, you think it out and decide.

Hi folks. I thought I'd share an adventure I have been having with my old 1974 Mercury 402 outboard. I live way up north in Amherst NH, and am the proud owner of my grandfathers old Terry Bass boat, which came with a 1974 Mercury 402 outboard. I became the custodian of "family" boat about 10 years ago and I look at it as an honor to keep the memory of my grandfather alive. However, I am finding it becoming more and more of a challenge to get the motor running in the spring. Usually I need to clean and rebuild the carburetor. However, this year has been a classic. It started off kinda like it usually does with the motor running rough, but then the motor got to where it barely would idle. And then if it was running, it would suddenly just die and refuse to restart until it decided it was ready.

So, I took it to a friend of mine who loves working on old motors and stuff and after messing with it for a day, we finally decided to clean the carb again so we took it apart and found water in the bowl. That was a surprise, but we cleaned the carb and then turned our attention to where did the water come from. The first place we looked was the fuel tank that was connected to the motor. We drained it, looked at the gas (which was Hi-Test and a week old) and no water. Then, we looked at the other tank of gas from last year, and found about a quart of water in bottom of the tank. Where the water came from, I have no idea. But, I had started off using that tank for the first motor run as usual so that was the source of the water. So, we were very careful to try to flush everything in the fuel system that may have been contaminated. The fuel line was flushed with air, and it had water in it. After that was clean, we fired the motor up again and the same thing was still happening - it would run and then just die. So, we pulled the plugs and they had water on them. Then we took one of those inspection cameras and looked inside the cylinders and saw the evidence of water on the rings so we assumed that we had water in the crank case, which made sense. So now, the problem became how do you get the water out of the crank case.

When I got the boat and motor, I bought a copy of the Mercury 402 manual on-line and kept a copy of it. The manual contained a discussion of what to do if your motor gets submerged. what the book said was to remove the motor from the boat, pull the plugs, put the motor in the horizontal position, plug side facing down, and them manually rotate the motor with a wrench for about 10 revolutions to purge as much water as possible. Once that has been done, pour a good amount of alcohol down the carburetor throat (alcohol absorbs water), and then manually spin the motor a couple of revolutions to pump the alcohol through the system. And then, pour motor oil into the carburetor and then manually spin the motor again. Once you have done all of this, put the motor back on the boat and see if it will start. If so, start the motor and run it for about an hour just to make sure all of the water has been purged from the motor. so, we did all of that today and the motor started and seems to be running about as it should. Now I am going to take the boat to the lake on Monday and run it around the lake for a while and purge the last of the motor, and finally I can go fishing. Morale of the story, don't get cheap by trying to use last years left over gas. I put stabilizer in the gas, Sea Foam, some Mercury enzyme gas treatment, and all of that stuff. From now on, last years gas gets tossed and I'm starting out fresh.