Yamaha 50 problem
Went out at Mindarie today for a fish. Left the marina and the motor, a 2001 50 hp yamaha 2 stroke, was running sweet. Motor only has 260 hrs and hasnt given me any trouble before. Chugging along on the plane about 2 kms out and the motor suddenly revs really high like the boat is cavatating almost and then the motor cuts out.
Started again and as soon as I tried to put any load on it it would just cut out. Fuel isnt overly old maybe 6 weeks. Serviced 60 hrs ago. I did notice that there was alot of oil on the transom before I left home but thought it was a leaky cap on the oil resivoir as I always stow the motor up and the tabs down to keep the pressure off the hydrolics.
Anyway had to limp back in at about 2 knts as thats as fast as it would go. Everytime I tried to put more power on it wouyld just cut out/ stop completley. After 45 minutes of crawling Im not happy and the wife was freaking out which didnt help. I specifically wanted this motor as I was told they are bullet proof but after today I'm not so sure.
When I got back in I hooked the hose up and the motor would rev freely without load but is running rough as. Checked the plugs and they seemed fine. Gave them a clean and didnt make any difference. Checked all the obvious stuff but it all seems fine.
Does anyone have any ideas before I take it to the shop and get that cash register look from the guy behind the counter who is now planning his kids college education at my expense. Had a look through the forums but didnt find much that helped. ANY help would be greatly appreciated
Starbug
Posts: 563
Date Joined: 27/08/09
All the symptoms point to
All the symptoms point to fuel starvation.
Could be anywhere from your tank through to the carby.
stilly
Posts: 341
Date Joined: 10/08/09
as above
symptoms point to fuel where are you located?
Gav475
Posts: 393
Date Joined: 16/11/11
Yeah dunno, there was heaps
Yeah dunno, there was heaps of sooting on the transom when I got back indicating unburnt fuel. Had the carbies stripped and cleaned 60 hours ago and nothing else has changed. Was thinking maybe a coill or something. Located NOR, Landsdale
stilly
Posts: 341
Date Joined: 10/08/09
sep filter
have you emptied your water sep filter? may have got some water in the system blocking your idle circuits, generally yams are bullet proof on the electrics side
stilly
Posts: 341
Date Joined: 10/08/09
test
if your suspect on a coil get it to fault again out on the water and pull leads off one at a time will soon tell if its ignition or fuel
Gav475
Posts: 393
Date Joined: 16/11/11
No but I will. Thanks
No but I will. Thanks
chookc
Posts: 442
Date Joined: 07/01/10
maybed a pin prick hole in
maybed a pin prick hole in your fuel line or fuel primer bulb...
fisherking
Posts: 730
Date Joined: 29/05/08
Sounds like air/fuel prob.
Sounds like air/fuel prob. Did it run any better/ worse on choke?
Plugs may look like new, but could break down under load.
Could be a lead.
Just a few, cheap suggestions.
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meglodon
Posts: 5981
Date Joined: 17/06/10
got to agree with other comments about fuel
i agree with other comments your description of the fault certainly indicats fuel starvation to me, i would be looking for a blockage in the fuel filter i hope you get it sorted with no cost and quick before weather puts the kybosh on fishing
Travisd
Posts: 315
Date Joined: 07/05/11
clip on fuel line
check that clip that connects fuel to the motor. The inside seal can blow out and will suck in air. let us know how u get on
Baron Sportsman
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Gav475
Posts: 393
Date Joined: 16/11/11
Thanks for the help lads,
Thanks for the help lads, much appreciated.
iana
Posts: 652
Date Joined: 21/09/09
My quess is the mixture leaned out.
"The motor suddenly revs really high like the boat is cavatating almost and then the motor cuts out".
That what happens when the carbie runs out of fuel.
"Had the carbies stripped and cleaned 60 hours ago".
Just wondering if one or all carbies have become loose, or the manifold gaskets are leaking (damaged), because the carbie/s are loose.
Fuel pump?
Adam Gallash
Posts: 15613
Date Joined: 29/11/05
Fuel
With the others, sounds like fuel. Make sure your fuel line is running the right direction, i cant remember exactly but i thought the primer bulb would be closer to the tank. Otherwise what the others have said, air intake or fuel seperator could be the issue.
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glastronomic
Posts: 892
Date Joined: 16/02/11
Is the fuel line the 2001
Is the fuel line the 2001 original?
if so then that would be the first item I look at and if not 100% replace.
Paul H
Posts: 2104
Date Joined: 18/01/07
As above would also be
As above would also be looking at the fuel side of things.
Also if an oil injected motor is lacking fuel it usually pumps in more oil to compensate which may explain the oil on the transom as well. If you don't already have one I would also whack a fuel filter on the fuel line between the bulb and motor and replace this every two years - costs around 2-5 bucks and is cheap insurance.
Cheers
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kane
Posts: 1752
Date Joined: 07/12/08
fuel tank built into the boat?
or the portable type? had an embarrassing moment as a teenager when motor kept dying...finally realised the fuel tank vent was closed (portable fuel tank)
but as others have said it definately sounds like a fuel problem - theres multiple things that could cause it so its just a matter of patience methodically working through the fuel system checking everything.
Gooooone Fishin!
Rob H
Posts: 5747
Date Joined: 18/01/12
process of elimination, but
process of elimination, but sounds like fuel for sure.
Drain water trap, change filter. If there isnt one FIT ONE!
remove hose from clip at outboard, squeeze bulb. Fuel should squirt out (bulbs sometimes fail)
reconnect, pump bulb, does it get hard or firm after a few squeezes indicating carby bowls full? If not it maybe the bulb still. A trick is to squeeze the bulb, kink the fuel line AFTER the bulb then let go bulb to fill. Kink before bulb and squeeze bulb to push fuel thru.
If fuel is getting to the engine, chuck boat in the water, tie it up firmly and start. If its still playing up try either choke or squeezing the bulb which could indicate a pump prob/blockage. From there its a mechanics prob if your not mechanically minded.
good luck mate!
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Gav475
Posts: 393
Date Joined: 16/11/11
Bad fuel
To cut a long story short the cause of the problem was bad fuel. When the filter and carbs were removed they were full of black sludge which must have come from the last time I put fuel in the boat and got the dregs from the servo tanks. Spewin. Mega buck for their stuff up. Thanks to all the lads that replied and you were all spot on. Just goes to show that even when you prepare your boat as best as you can shit still happens.