2001 Nissan 140HP not staying on, fuel starvation?

[spacerust]

I recently got a used 2001 Nissan 140HP. Compression reads 150 to 152 on all cylinders. Carbs have been cleaned and synced and when we ran it at the guys house started right up and no problems and revved it, no issues. When we placed it on my boat I had to drive a few hours through hard rain and when I got home and tried to start it the next day, it started but died after awhile. I looked and started with the primer. I primed it and some gas came out. then I hooked it up to the fuel line that goes to the diaphram, seemed ok, the it would stop at the fuel pump. So I called the guy I bought it from (he works on Tohatsu/Nissan motors) and he had me do a few things over the phone (he lives 500 miles away) and determined it may be the fuel pump. He sent me a brand new one. I bought a new primer, put new hoses from the primer all the way through to where the fuel line goes to the carbs. Primed it up and it ran, let it idle for a bit and then when I gave it gas it struggled and turned off. I primed it again and it seems like I am not getting a good fuel run to the carbs. When I am priming the bulb, I am looking at the diaphram and it seems like it's tryin to get fuel but not filling up. I'm not sure if there may be a kink in the hose somewhere from the fuel tank to the primer. I did notice also that my fuel gauge stopped working but I have almost a full tank of gas. Any suggestions as to what to check. I called the guy up and he is really cooperative and said if I need any parts he would send them to me but when we were at his house it ran great, but I realized that it was from a hose from a gas tank. So the only thing that has changed is his tank to my tank. My motor ran great too before I placed this motor on. Any suggestions, tomorrow I am going to try and disconnect the hose from the primer bulb and pull it out to the fuel tank to check for any holes or I am not sure, but it seems like it's not getting a good fuel running through. I do have an water seperator running through after the primer, but the filter is only about a month old. I would appreciate any advice on what I could check. Thanks in advance.

 

[pvanv]

Re: 2001 Nissan 140HP not staying on, fuel starvation?

Grab a Factory servicer manual and start diagnosing. You may have a bunch of water in the fuel (from the rain) or something more severe.

 

[spacerust]

Re: 2001 Nissan 140HP not staying on, fuel starvation?

Ok, I took out the fuel hose from the pipe underneath where it travels to the fuel tank to check for any punctures or kinks. Hooked the hose back up to the primer bulb, and took the quick connect off and hook it directly to the diaphram. When I started to prime the bulb I noticed the diaphram was leaking it small bit. I tightened snug and when I started to prime again it sucked it right up and the motor on excellent and ran fine. I would turn it off, wait some time and tried it again. I would let it run a bit and revved it to just to check it. I decided that there was probably air in the diaphram creating a pocket not allowing the gas to fill it. I hooked the quick connect and then when I primed it didn't want to catch again. I noticed an air pocket in the diagram and figured this was keeping it from filling with gas. Two questions. First, how do I or where do I release the trapped air and second, does the quick connect have to be a certain size. This quick connect was on my 90HP when I had it and now this motor is a 140HP. Would that restrict fuel flow?

 

[pvanv]

Re: 2001 Nissan 140HP not staying on, fuel starvation?

If you have a leaky o-ring on the primer hose, you could suck air. Air in the line should get purged along with the fuel, and bubble up to the top of the carb bowl. If the primer bulb does not get firm after the air was purged, either the check valves in it are bad, or you have an air leak. Tank-side connectors are all the same on all current Tohatsu motors.

 

[TOHATSU GURU]

Re: 2001 Nissan 140HP not staying on, fuel starvation?

Yes, the fuel connector is the wrong one for your model engine and does not allow enough fuel flow.