fuel starvation-where to start

[hoboturkey]

Hi, I have a 2 stroke yammie 40 veto, 2009 model with 130 hours. I have bought this about 5 hours ago and it looks like new.
I have had about 6 trips only and at first running at over 4000 rpm was easy. The last 3 trips I have had trouble getting anywhere near that. I managed to increase it from around 3 thousand to near 3400 by spinning the fuel tanks around to aid the pickups and was happy to travel with low fuel usage till I could sought some advice. I took it on a nice flat river 3 days ago and was sitiing on 3400 rpm when I pushed the throttle arm to the max and it died with a 5 second run when I put the red leaver to emergency. Lucky I had a mates boat to tow us.
I have it at home now, when I squeeze the fuel bulb I can hear a reaction in or around the triple carbys but have not managed to see fuel come from the jets.
Would anyone have a list of the first ten things to check.
The fuel is fresh
I checked the service manual and the settings from the last service seem to be ok- advance indicator, neutral starting position etc.
All 3 carbies no fuel from jets, spark plugs disconnected, air filter off, idle increase lever up, bulb tight, and cranked.
Thanks in advance as that tap on the throttle lever has me thinking there is a stuck mechanical something.
dave

[almetelo]

Seems you may have a problem on fuel pump or a leak on your fuel line / system.
If when you squeeze the bulb it runs normally is probably a fuel pump problem.

[99yam40]

Hi, I have a 2 stroke yammie 40 veto, 2009 model with 130 hours. I have bought this about 5 hours ago and it looks like new.
I have had about 6 trips only and at first running at over 4000 rpm was easy. The last 3 trips I have had trouble getting anywhere near that. I managed to increase it from around 3 thousand to near 3400 by spinning the fuel tanks around to aid the pickups and was happy to travel with low fuel usage till I could sought some advice. I took it on a nice flat river 3 days ago and was sitiing on 3400 rpm when I pushed the throttle arm to the max and it died with a 5 second run when I put the red leaver to emergency. Lucky I had a mates boat to tow us.
I have it at home now, when I squeeze the fuel bulb I can hear a reaction in or around the triple carbys but have not managed to see fuel come from the jets.
Would anyone have a list of the first ten things to check.
The fuel is fresh
I checked the service manual and the settings from the last service seem to be ok- advance indicator, neutral starting position etc.
All 3 carbies no fuel from jets, spark plugs disconnected, air filter off, idle increase lever up, bulb tight, and cranked.
Thanks in advance as that tap on the throttle lever has me thinking there is a stuck mechanical something.
dave

Motor should turn 5500 RPM at WOT if running right and propped correctly.

I would check compression, spark to all plugs, check timing at idle and when raising RPM to see if in spec, test fuel pump pressure and vacuum.

If all is good the pull carbs and clean than adjust like service manual after reinstalling.
Clean tank and lines if trash is found in carb bowls.

Motor should have the prime start/ enrichment system and no choke. shaould be in the normal position unless there is a carb plugging problem then move red lever to emergency position to start and then to the off position to make back to port to fix it.
Should not have to use the fast idle lever when starting.

Pulling plug wires and turning over with noy shorting the plug wires to a ground can harm the ignition system(spark where it should not, and cause voltage spikes harming components)

"that tap on the throttle lever" not sure what that means

[hoboturkey]

thanks almetello

Seems you may have a problem on fuel pump or a leak on your fuel line / system.
If when you squeeze the bulb it runs normally is probably a fuel pump problem.

When I squeeze the bulb and push the ball in on the connector at the motor end fuel comes out. no visible leak. It was running until dead stop.
Sqeezing it makes a fizzing noise at the carbs, so I am trying to get fuel to pump out the jets in the carby throats.
thanks

[hoboturkey]

thanks 99yam40

Motor should turn 5500 RPM at WOT if running right and propped correctly.

I would check compression, spark to all plugs, check timing at idle and when raising RPM to see if in spec, test fuel pump pressure and vacuum.

If all is good the pull carbs and clean than adjust like service manual after reinstalling.
Clean tank and lines if trash is found in carb bowls.

Motor should have the prime start/ enrichment system and no choke. shaould be in the normal position unless there is a carb plugging problem then move red lever to emergency position to start and then to the off position to make back to port to fix it.
Should not have to use the fast idle lever when starting.

Pulling plug wires and turning over with noy shorting the plug wires to a ground can harm the ignition system(spark where it should not, and cause voltage spikes harming components)

"that tap on the throttle lever" not sure what that means

The tap on the throttle means I was running fine, although the rpm ceiling was only 3400 when I used the palm of hand as a gentle hammer on the handle expecting a final millimetre of travel might give me 3500. That was when the motor refused to start except when I used the emergency position on the red lever which gave me a rough start of a few seconds and then stalled.
I only used the fast idle arm wondering if opening the valves in the carby might allow fuel to come out the jets and thus cancel fuel as a possible cause of the problem.
I turned the motor for a couple of seconds only and wont do it again without the plugs in, but I do wonder how to do a compression test without doing so. Did you mean not grounding the plug leads which I made sure would not happen.

The tap on the throttle is a strange cause, and yes I will need to get the motor up to proper rpms.
dave

[99yam40]

The tap on the throttle means I was running fine, although the rpm ceiling was only 3400 when I used the palm of hand as a gentle hammer on the handle expecting a final millimetre of travel might give me 3500. That was when the motor refused to start except when I used the emergency position on the red lever which gave me a rough start of a few seconds and then stalled.
I only used the fast idle arm wondering if opening the valves in the carby might allow fuel to come out the jets and thus cancel fuel as a possible cause of the problem.
I turned the motor for a couple of seconds only and wont do it again without the plugs in, but I do wonder how to do a compression test without doing so. Did you mean not grounding the plug leads which I made sure would not happen.

The tap on the throttle is a strange cause, and yes I will need to get the motor up to proper rpms.
dave

you need to pull the kill switch when turning over motor when you do not want it to fire the plugs.

Opening the throttle plates will add air not fuel

Pull the carbs and clean

[hoboturkey]

thanks 99yam40

you need to pull the kill switch when turning over motor when you do not want it to fire the plugs.

Opening the throttle plates will add air not fuel

Pull the carbs and clean

I have an ignition key, where is the kill switch ?
Is there a way to see the jets spit fuel ?
Dave

[99yam40]

safety lanyard that you hook up to yourself in case you fall overboard.
It pulls the clip off of the kill switch

Not on the idle circuits

[hoboturkey]

Thanks mate

safety lanyard that you hook up to yourself in case you fall overboard.
It pulls the clip off of the kill switch

Not on the idle circuits

thanks mate cheers

[throrope]

Good judgement comes from bad experience.

First, get the service manual. YAMAHA MANUAL STORE

Since its new to you, I'd toss the fuel delivery from connection at the engine to and including the tank. Replace with stuff listed for ethanol and add a fuel/water separating filter. Our ethanol fuel gums everything just sitting.

Then with a clean fuel system, move on to the carbs. Drain the bowls and see what comes out. If its crap, get what you need here and go through them. Sometimes the individual gaskets are less than a kit which may not have everything.

Posts here provide great guidance and all the above costs less than a failed trip.

I empty the fuel, drain the carbs and leave the tank upside down with cap off after every trip if not going out again tomorrow. I rigged a cheap fuel pump with a 12 volt plug, fuel hose and connector to pump out the boat into the car. No fuel, no fuel to go bad. Amazon.com: Autobest F4027 Electric Fuel Pump: Automotive

[wildturkey]

Could be your fuel pump. I think there is one for low speed and one for hi speed. Just a guess! Mine went out and it was not getting decent rpms. Also, pay attention to the bolts not tightened enough that could cause an air leak on the side of those pumps. That caused me some major running problems on my boat until I tightened the 1/4x20 bolts on the pumps. My engine would surge while running at higher rpms.