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KentuckyArcher
Kentucky Fan
Slidell
Member since Aug 2012
107 posts

Yamaha 50 runs but no power, won't plane
I got a 2003 Yamaha 50 on a 16ft seaark. This morning at daylight, launched the boat, engine is a little cold natured but after 5 minutes everything seemed normal. Proceeded to idle down the pearl river and went to open in up . NOTHING!!!! It's not missing or running rough at all. Just won't plane out. Almost like I was pulling another boat.Or that I had a 20 hp instead of 50 hp. Anyone have any suggestions on what to check. I really don't think it is the carbs due to the fact that I tore them down June 1st cleaned them. Back then they weren't really dirty. I also ran the gas completely out of motor the last time I ran it. Gas tank was completely drained and cleaned 3 days ago. Fresh gas purchased this morning. Any help would be appreciated. Thanks



Ole Geauxt
LSU Fan
KnowLa.
Member since Dec 2007
48859 posts

re: Yamaha 50 runs but no power, won't plane
check prop?


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LSUray
LSU Fan
Shreveport
Member since Sep 2003
1383 posts

re: Yamaha 50 runs but no power, won't plane
It's not hitting on all cylinders. Clean your spark plugs off and see if it works. If not, replace them.


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LSUwag
LSU Fan
Florida man
Member since Jan 2007
13773 posts

re: Yamaha 50 runs but no power, won't plane
quote:

ran the gas completely out of motor the last time I ran it


You probably picked up some debris from the fuel tank.

Sounds like it isn't getting enough fuel to run WOT.


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Boats n Hose
LSU Fan
NOLA
Member since Apr 2011
37241 posts

re: Yamaha 50 runs but no power, won't plane
Debris in carb jets or fuel lines. That was the problem when it happened to us. Except it was caused by leaving ethanol gas in the fuel lines over winter, fuel lines broke down. Replaced lines, cleaned carb, ran fine


Bigpoppat
Army Fan
Drinking a Manhattan
Member since Oct 2008
8687 posts
 Online 

re: Yamaha 50 runs but no power, won't plane
Make sure your choke isn't out


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LSUwag
LSU Fan
Florida man
Member since Jan 2007
13773 posts

re: Yamaha 50 runs but no power, won't plane
quote:

caused by leaving ethanol gas in the fuel lines over winter, fuel lines broke down


I use ethanol free gas and I never allow the tank to go below 1/3. The gas is hard to find but, worth the effort and extra price.


Boats n Hose
LSU Fan
NOLA
Member since Apr 2011
37241 posts

re: Yamaha 50 runs but no power, won't plane
We do now, and run the gas out of the motor when it'll sit up for a while. This was right after we got the motor running but had a lot of work to do on the boat, and huntin season came, we hadn't run that motor since before the advent of ethanol fuel and didn't know it would happen.


LSUwag
LSU Fan
Florida man
Member since Jan 2007
13773 posts

re: Yamaha 50 runs but no power, won't plane
I learned my less after screwing up my lawn equipment. Ethanol fuel is really bad stuff.


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greasemonkey
Alabama Fan
Macclenny Fl aka south JAWJA
Member since Aug 2012
2642 posts

re: Yamaha 50 runs but no power, won't plane
If it idles good its not likely to be the plugs..
If its not reving up like it should, have someone pump the bubble as you are trying to get on plane..
If that doesnt help you more than likely have a plugged hi speed jet or water in the carb..
there is a drain plug on the bottom of the carbs, remove these and try to catch the gas in something clean, so you can see if theres any water or trash..
It only takes a very small piece of trash to clog the main jet.
If its never had new fuel lines or your not sure replace them every 2 years. very cheap insurance

If it is reving up but not getting up to speed or on plane You have a spun hub in your prop..

hope this helps..



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Cold Pizza
Ohio State Fan
Member since Sep 2011
7639 posts

re: Yamaha 50 runs but no power, won't plane
It may be as simple as a plugged fuel strainer/filter. Check that first.


LurkingTiger
LSU Fan
Member since Mar 2010
67 posts

re: Yamaha 50 runs but no power, won't plane
It's sounds like you spun the prop. I would take of the prop and look to see it the rubber bushing is ok.


redfish99
LSU Fan
B.R.
Member since Aug 2007
6740 posts

re: Yamaha 50 runs but no power, won't plane
It's sounds like you spun the prop. I would take of the prop and look to see it the rubber bushing is ok.



This


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Cracker
Montana Fan
in a box
Member since Nov 2009
9690 posts

re: Yamaha 50 runs but no power, won't plane
Its the carbs pull the bowls off blast it with carb cleaner jets and any where you can get cleaner into it its the ethanol gel hell


greasemonkey
Alabama Fan
Macclenny Fl aka south JAWJA
Member since Aug 2012
2642 posts

re: Yamaha 50 runs but no power, won't plane
Does anyone read the other post.....

no power sounds to me like no revs if prop was spun it would rev hard but not go. OP said no power.

OP doesnt use ethanol and just cleaned carbs..
that doesnt mean it doesnt have trash or water in it though..



First I would check fuel filter as cold pizza pointed out,and that the bulb isnt getting soft.. pump while trying to get on plane.. both of those will cause same symptoms..
if not those drain bowls to see what comes out before just pulling them

By the way this is how I make my living..


KentuckyArcher
Kentucky Fan
Slidell
Member since Aug 2012
107 posts

re: Yamaha 50 runs but no power, won't plane
I'm pretty confident it's not the prop because the motor does not rev hard. I don't use ethanol fuel, I run a water/filter separator, gas tank is clean. I guess I'll tear down them carbs again and see what I can find. Thanks everyone for your help..


DownshiftAndFloorIt
LSU Fan
Here
Member since Jan 2011
52659 posts

re: Yamaha 50 runs but no power, won't plane


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hogdaddy
LSU Fan
harvey
Member since Feb 2010
4844 posts

re: Yamaha 50 runs but no power, won't plane



Yamaha limits engine speed agaInst damage for various reasons.

1: Coil
2: CID
3: temp switch
4: 2 Stroke oil level switch

I'm going to say the level switch, as I had the same type of problem with my fathers 2000 Yamaha 90. I'd haven't had any more problems since I change it out.


Kyrie Eleison
LSU Fan
Waco, Texas
Member since Jul 2012
1175 posts

re: Yamaha 50 runs but no power, won't plane
You either spun the hub in the prop (as mentioned above...and this is my best guess)...or a piece of varnish or other debris is in your fuel line.

Go to your dealer (or a friend) and borrow a prop, throw in the water and see if it jumps on plane. If it does, take your prop in and get a new hub put in it.

If it does the same thing, it's your fuel line.

Maybe...just maybe...assuming it's oil injected...your oil pump is out and pump governor is keeping you from hitting high rpms. But I doubt that given you said that you're power plant sounds fine.



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AlxTgr
LSU Fan
Kyre Banorg
Member since Oct 2003
65280 posts

re: Yamaha 50 runs but no power, won't plane
It's the plugs.


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