I'll try my best to describe my problem.
I have a 1999 Mercury XR-6 150 HP with 3 carburetors, and an after-market holley red electric fuel pump.
The problems began around the first of June. I had just got my boat back from having it polished, and having the carpet replaced. When I got it back, I took it out for the first time, and it did well at first. It took off normally and ran good. My wife and I stopped at a place to fish for a few minutes, then we decided the water was too rough so we were going to go somewhere else. I went to take off, and the problem began...
So at this time, I pushed the hot foot to accelerate, and take off, but instead the engine began to accelerate briefly, then it was as if it wasn't getting any gas, and it just revved down. I tried again with the same result, several times. Finally I realized that if I just barely pressed the gas I could go just a little bit faster than idle speed, but if I pressed it too hard it would "give out." I was far from the boat dock, and very upset (because I thought the people at the boat repair place messed something up). I finally opened up the battery box, and I noticed that the black wire from the fuel pump to the battery had come disconnected from the battery terminal. I replaced it and the boat ran fine for the rest of the day. I thought that solved the problem, but...
About 2 weeks later, I was out fishing, and I noticed that if I got the r.p.m.'s up above about 4500, the engine seemed to lose power, if I began to decelerate at all from there, the boat would rapidly lose power, and eventually it would just die, unless I quickly pressed the hotfoot down hard again, then it may or may not power up. Also, it began to have the same problem at take off too. I would go to take off, and it would begin to rev, then just lose power (like it wasn't getting gas). I would try several times, and eventually it would take off properly, but still, I could not get it above 4000 r.p.m's or it would begin to lose power and "lag" again.
I assumed that since I was having the same type of symptoms as I was when the wire came off the fuel pump that something must be wrong with the fuel pump. So Tuesday I bought a new fuel pump. I replaced the one that was in my boat with the same one, it is an after-market Holley Red Electric Fuel Pump. I thought surely that would fix the problem, but...
I took it out Tuesday afternoon, and it was doing the same thing. It would lose power several times before it would finally take off properly, and lose power beyond 4000 rpms, and die if I tried to decelerate. I called my dad. He suggested that I needed to replace the fuel filter, and spark plugs. So I did that Wednesday. Took it out Wednesday evening... Same thing.
When I got home I called my neighbor, who is an auto mechanic, and he looked at it and noticed that the fuel hose that was going into the bottom carburetor was kinked badly beyond 90 degrees. He said that fuel might not be getting to that carb, but added that even if it weren't getting any fuel at all, the engine shouldn't be dying like that. Then, Friday afternoon I talked to a man that used to race boats, and he told me that I might have something in my carburetors, and I should remove them and clean them thoroughly.
Well, yesterday afternoon, I put some fuel system cleaner in my gas tank, then I repaired the kinked fuel hose, then I sprayed my carburetors with carb cleaner (but I didn't break them down). I took the boat out yesterday evening, and guess what...
It's still doing the same thing.
The thought crossed my mind, that I might be still getting a bad connection to the battery terminal with the fuel pump wire. So this morning I checked the connection and it looked good. Then I took the fuel lines off the carburetors to clean them, I noticed that there was a filmy, gasoline colored, residue on the inside of the hoses. I took off each one of the hoses, and blew that stuff out of them, and sprayed some carburetor cleaner through them. I also cleaned the carburetors and cleaned the battery terminals. I took it out earlier this afternoon, and I thought for sure that cleaning those hoses would solve the problem, but now it's even worse than it was yesterday.
I am clueless now. I know it's not the starter because the starter is only about a year old. It has a brand new fuel pump, brand new fuel filter, and the hoses and carburetors have been cleaned.
What else could it be???
I have noticed that it idles perfectly, and it sounds perfect when I run it hooked to my water hose adapter, but when I actually get it in the lake, against resistance, that's when it won't work.
It's as if as soon as the engine senses water resistance at the prop, it loses power. Could it be that it needs a new water pump?
Any other suggestions? Thanks in advance.