[spinfreak]

I've been having a problem with my engine for almost a year now. I'll start from the beginning.
The outboard is a 1984 Mercury Blackmax 150 hp. Last year, I was in a 2 day fluke tourney. First day it ran fine. Second day, it ran fine in the morning. Then we went back in to get some more bait and use the bathroom. Headed back out, and when we got out of the inlet, went to give it throttle. The engine started sputtering, and there was no power. The engine ran fine at low rpm's, but there was no power when you got up to 2000 rpm's. It sounded like it was missing...kind of sputtered. Fished the rest of the day, but had to limp around.
Took the boat to the mechanic (this was july...I didn't get the boat back until sept). He replaced something or other (I forget what it was at this moment), but he said it should run fine. Didn't get a chance to take the boat back out again until December. Went to give it throttle, and the same problem as before...no power over 2000 rpm's. Called the mechanic on the phone and told him the boat was still having the problem. He sais to wait until spring. In the meantime, he said that it could be the fuel pump. Over the winter, I rebuilt the fuel pumpo and the water pump while I was there. Didn't get a chance to take it back to the mechanic, but was hoping that it was just the water pump causing the problem.
Finally got a chance to take the boat out yesterday. The problem is still there, only now it's even worse. It won't go over 1600 rpm's. The engine sounds like it is missing or soemthing. When we got back in, I ran the motor to wash it out. The stream of water coming out comes out strong for a second, and then gets weak for a few seconds before getting strong for another second. So it seems like the engine is speeding up, and then slowing down slightly while at idle...but you can't hear it slowing down though.
Talked to the mechanic, but he's backed up. I don't want to take the boat to him because he'll probably have it the whole summer again, and I want to be able to go out fishing again before the end of summer.
Does anybody have any clue what the problem might be?
If you might be able to help, or need any more info, please e-mail me at [email protected]. (I don't get too many chances to come on this site anymore, so e-mail would be easiest to contact me).
Thanks a bunch, and tight lines,
~steve~

 

[621848]

Spinfreak,
I think it comes down to the same basic problem most engines have....fuel...and spark. Since you have a 2 stroke timing is not an issue. My first thought is fuel,mostly because of the surging you are seeing. It sounds like your fuel system is not suppling enough fuel to the motor at high rpm's. Your car will act the same way if the fuel filter is clogged. You said that you rebuilt the fuel pump? Did you change your fuel filter? Take down your carb(s) and clean them? Change/clean your air filter while you are there...it's not your problem, but if it's dirty...it's not helping it.
The next scenero is spark. But since you started having problem all at once I would suspect fuel first. If you still have problems after checking the fuel system, post another not and I'll go into the spark end of things. Let me know WHEN and how you fix it.

Also...I suggest getting a new mechanic. One that will say "It ran fine when I took it out and tested it." Not one that says that says "It should run fine" meaning "I just ran it with a garden hose attached with no load. If it works..it works".

Good luck!

 

[brianf]

I had a similar problem with my I/O motor. After replacing the fuel pump, rebuilding the carburator, replacing the ignition coil, all new fuel lines, the problem still existed. I bypassed the fuel tank by running the boat out of a 5 gallon container of gasoline connected to the fuel pump. The boat ran perfect. I discovered a small fuel filter in the pick up tube of the fuel tank, which was totally clogged. I simply removed this filter and left it out of the fuel tank. The boat has been running absolutely perfect this entire season thus far.Try to find the filter in the pick up tube of the fuel tank. This might be your problem. Goood luck

 

[spinfreak]

Thanks for the replys.
Rodbuster: No, I didn't change my fuel filter, but I did change it last year. I didn't clean the air filter either (I didn't even know I had one?!?!). And I never mess with the Carb, because I don't know much about them. I'm going to try to get down by the boat next weekend, and work on it, and see what happens.
Brianf: Your suggestion sounds like it might be a possible reason. I had a similar problem on a van that I owned a few years ago. After I check the filters, etc, I'm going to take the boat out for a spin, and bring along a 5 gallon tank to try that out. If it runs good, then I know the problem is in the boat's fuel system, and not the engine's.
Also, the mechanic that did the work originally, told me that I should install a water seperator (the type with the bowl that seperates the water from the fuel. Would this help at all in the long run, or not? Thanks again. If anybosy else has any suggestions, please let me know.
~steve~
[email protected]

 

[spinfreak]

OK...I went down yesterday and pulled off the carbs. I know that it probably isn't the problem, but since I've never cleaned them in the 8 years that I've had the boat, I figured it's about time to do some cleaning. I took a look throught the manual, and it doesn't seem too difficult to do (and besides...I love tinkering with stuff anyway...lol).
Then I'm going to try runnoing the boat on a portable tank, to see if I can rule anything out.
Thanks again,
~steve~
[email protected]
p.s. Does anybody have any suggestions regarding a fuel/water seperator? Thanks

 

[spinfreak]

one other question. When I re-build the carbs, should I get the complete carb re-building kit, or just the gaskets?
Tahnks again.