Motor bogs down at full throttle

[floatfisher]

I had my boat out on Seneca on Friday with my cousin.  Finally had a bit of time to get it out, need to get it out more often especially since I am going to be taking it up to the 1000 islands on a family vacation.  Anyway, I had the motor wide open to see how she was running and we were just going to cruse around for a bit when all of the sudden we slowed right down to almost trolling speed.  This all happened while I had the throttle all the way down.  Today I took my fuel filter off and it looked like new.  I was going to check my spark plugs but ran out of time this afternoon.  Anyone know what could be going wrong?  I still may get a new filter and change it out anyway.

 

Thanks for any help!

[Willy-C]

I don't know your boat or motor but if it was mine and I was suspecting fuel issues the first thing I would do is find an aux fuel tank (with fresh fuel)and connect directly to your engine to rule out bad fuel or fuel delivery (restriction in fuel system)

At least it will give you a direction to start...... in the engine or the tank/lines/filter

Edited August 11, 2014 by Willy-C

[Pete Collin]

That happened to me once when I had water in my gas. 

[Knotlost]

Go through the easy checks, Gas, gas and gas, ethanol is a killer try to only buy non-ethanol and always use something like starbright fuel conditioner even with good fuel.  If you have bad gas in the bowl of your carb just changing your filter will not do it. You have to KNOW from the carb back you have good fuel.

[floatfisher]

So I forgot to mention the boat is a Spectrum 1706 and has a 90 hp Force.  Does anyone know if the built in gas tank has a filter on the tank?  Could there be a sending unit problem?  I have been thinking about replacing it anyway as my gas guage is verry irratic to say the least...

 

I figured that it was a gas problem, and I have added additives to the fuel.  Last year I used some seafoam and added some Starbrite, this year when I put my gas in I used the Starbrite again.  Can you use too much of the stuff, maybe I did not use enough?

 

Pete - when you had water in your gas, what did you do?  Empty your tank or add something to it?

 

Tahnks again guys!

[G-Daddy]

We had the same thing with our brand new 350 Mag inboard first day of fishing this summer.  Engine ran great on the run out to the fishing grounds and trolled all day and bogged down on the run in.  The closer home we got the worse it bogged.  Got into the river and she idled fine.  Turned out it was a clogged fuel filter, even though it looked good.  Try the simple things first.

[Willy-C]

If you haven't already you may wanna change all the gas lines from tank to engine......older gas lines can swell up inside due to ethanol and cause much trouble

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[lineman49]

K-100 gas treatment!! IT works!

[Reelfanatic]

If hub in prop has spun, you will have a problem like that as well.

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[Pete Collin]

floatfisher,

 

I can't remember exactly what I did.  My gas tank can't be drained, so i probably put dry gas in and ran the tank way down before refueling. 

[SylvanTroller]

I had bad gas cause this once try a different tank as mentioned above. A different time ethanol fuel had delaminated the inside of my fuel line clogging the line. Was very surprised when I pull the line off and saw it. Good luck and let us know how it turns out.

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[GAMBLER]

I had the same issue and there was crap in my fuel tank that kept clogging the fuel pick up in the tank. At higher speeds it was an issue. If I went slow it was fine

[Firechief48]

Floatfisher I hope by now your problem is solved but if not I had the same problem as Gambler with the pickup tube clogged.

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[Has Been]

I just got back from the ADK's and my motor did the same thing. Took my Carb off at the campsite & rinsed ti out w/ WD 40 ,which is all I had & dumpped it on a white paper towel. A small piece of fuel line I think  , and I mean small,about the size of a period on here came out. Put it back together & it ran like a top.35 merc.

Edited September 10, 2014 by Has Been