Full Throttle Half Power

[Todd2]

Took my boat out today. Everything was fine for a mile or two but then lost power. It's a Tracker 40 HP...nornally cruises around 25 to 30 full speed. After the power loss,  I couldn't get it over about 5mph full throttle back to the dock. Im replacing the plugs and fuel filter tomorrow. Any other ideas? 

 

Thanks

Todd

[Gundog]

A friend of mine had a similar situation and he replaced the fuel filter, as you said you're gonna do, and changed the gas as well as adding some fuel additive. I believe he said it was Seafoam. 

[iabass8]

Could be a number of things. Do your RPMS go up but speed doesn't? If so, I would check your prop for a spun hub. If the RPMS don't go up..it could be a number of things as simple as gas, dirty carbs, clogged instake,  being down a cylinder or over heating. 

[fishnkamp]

Does that have a portable fuel tank or a built in one. If it has a portable check to see that the vent is open.  If it has a built in on then make up a spare fuel line and try running it from a portable gas can.  Also did you check the fuel primer bulb when you lost power, there has been issues with those primer bulbs. When I got my Lowe brand new it had that problem straight from Mercury.  If you have been forced to use ethanol you may need to replace the fuel line from the tank to the primer bulb and from the primer bulb to the engine.  Ethanol causes the inside of the fuel lines to break into a powder causing fuel issues. I have had to do all of that on my boat.  

Iabass8 good catch on the prop, forgot about that one

[RoLo]

I can only hazard a guess, but it does sound like a 'fuel' issue,

rather than spark or compression.

 

Roger

[Todd2]

Thanks to all...I'm not always able to buy ethanol free so I'm going to check/replace those lines/bulb too. No revving so I don't think its spun hub. Feels like a fuel issue. Thanks to everybody. I'll report back.

[Ski213]

I would think it's likely one of the above mentioned issues, and I would start there, but if everything checks out up top be sure to check out the lower unit. 

["hamma"]

If its not the fuel? it may be a coil, check for spark. My 87 merc 35 hp had this as a issue, I upgraded to a newer elec start elec trim 40 anyways, but was told by the mechanic the 35's issue was spark

[Slade House]

okay, I have a 2005 Bass Tracker 50HP 2 stroke.  Here is the thing you most likely need to replace your fuel lines that go from the tank to engine itself.  and you need to clean or clear out your fuel filter (make sure you put it on the right way).  

 

Engines prior to 2006 have gas lines that weren't designed to handle the amount of ethanol in our gas today. So what happens is that ethanol fuel gradually eats away the protective inner lining on those Fuel lines and sloughs off and ends up clogging your fuel filter.  I know cause this exact problem happened to me.

 

 my advice is to replace those fuel lines, and clean and the fuel fliter.  

[Bass Turd]

Replace the fuel line or check that clamps are tight from the tank to the engine. I've had it happen several times just as you describe. I had an air leak at anything above idle so instead of sucking fuel it was sucking air into the engine.

[Al Wolbach]

45 minutes ago, Slade House said:

okay, I have a 2005 Bass Tracker 50HP 2 stroke.  Here is the thing you most likely need to replace your fuel lines that go from the tank to engine itself.  and you need to clean or clear out your fuel filter (make sure you put it on the right way).  

 

Engines prior to 2006 have gas lines that weren't designed to handle the amount of ethanol in our gas today. So what happens is that ethanol fuel gradually eats away the protective inner lining on those Fuel lines and sloughs off and ends up clogging your fuel filter.  I know cause this exact problem happened to me.

 

 my advice is to replace those fuel lines, and clean and the fuel fliter.  

 FWIW  Yamaha engines did not experience this problem. Their fuel lines were compatible with the mix.

[Fishing Rhino]

Does your engine have an electronic control module?  If so continue reading.  If not, disregard my advice.  

 

For it to happen suddenly, rather than gradually sounds like the computer for the engine is sensing a problem and will not allow the motor to be run over a certain rpm, usually idle.  Could be any number of things that will cause the computer to limit the power the engine can produce.  

 

You can drive yourself crazy doing a trial and error search for the problem.  But if it were me, I'd pay to have a tech hook it up to a computer and diagnose the problem.  

 

 

[Todd2]

Thanks again to all. I replaced both plugs, fuel filter, and the fuel line/bulb. Runs like new. Not sure which one was the culprit but I''ll just consider it maintenance for the other two. 

[RoLo]

10 minutes ago, Todd2 said:

Thanks again to all. I replaced both plugs, fuel filter, and the fuel line/bulb. Runs like new. Not sure which one was the culprit but I''ll just consider it maintenance for the other two. 

 

I'm glad you solved your problem, which can sometimes be a hassle.

It's history now, but I suspect the fuel filter might've been the problem.

Usually, when the fuel line is involved you'll feel it in the bulb pressure or see gas leakage around an O-ring.

In any case, good deal

 

Roger

[Wurming67]

Good to hear I had same issue I replaced fuel lines and tank solved the problem I got an old boat so I use ethanol free gas it's more money but well worth it in long run.