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What would happen if one was to pinch the fuel line in various places on a good motor while running? Would the fuel level in filter pulse like the video? I have mechanical fuel pumps so I don’t know if it would be a good comparison.
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yea, pressure and vacuum readings could help see what is going onOriginally posted by fairdeal View PostComment
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Happy Memorial Day all . Today I’m protecting the public so I have time to think about my next move. I think I need to start again and go over the entire fuel system from tank to pump. I’m going to order the diagnostic program and plug this motor in. I need to start fresh and look for leaks and restrictions. At this point I feel if I replaced the entire fuel system it would still die out.Comment
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Have you at least checked the readings as suggested by Fairdeal in his last post?Originally posted by marchmadness View PostComment
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I will try to check the pressure in and out just not sure how to plumb it in.Comment
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I have also read some have experienced corrosion on the wire connecting the lift pump.Comment
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Todays findings; started with a cold motor I haven't touched it ,cup did not due the crazy up and down fill. working like the other motor. I hooked up the motor to the Yamaha diagnosis . No fault codes , nothing came up. ran the boat for about 20 minutes let it sit for 30 hooked it back up all worked . I brought it back to the dock let it sit again , there was a brought it back up to 1800 and it didn't die. I then ran it on a portable tank to see if there was a difference. no difference.Comment
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Since my issue only happens after hot if the vst vent doesn’t let the pressure out that pressure could cause the relief valve to stay open?Comment
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this is still the same problem/symptoms from your first post in 2016?
the "relief valve" limits the "head pressure" of the LP pump to ~15 psi.Originally posted by marchmadness View Post
Unless you have Hulk-like hand strength, you are not getting more than that with the primer bulb.
But if you want to "test the influence" of the VST venting,
the simplest thing to do is connect a couple feet of suitable tubing,
and run it directly to outside the cowling -
perhaps remove the filler plug for the unused T/T switch
that way the VST can "breathe" unrestricted -
(and if its "boiling off" its contents, you may be able to perceive that)
within the Gordian knot of tubing at the top of the VST,
are the two small hoses from the vent ports, Tee'd into one larger
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Let me explain my thoughts. My issue only when the motor is hot and after a shut down. Vst is a small gas tank when it gets hot gas pressure builds inside . Pressure build up in the system I think is causing the pressure relief valve to open and stay open not allowing the vst to refill when the throttle opens. I am planning to remove the vent orifice and replace it with a low pressure fuel check valve and run the vent out of the motor. I have read other posts on this issue and it seems to fit , this is caused by heatComment
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I ordered a one way check valve that I’m going to install to replace the vst Orefice valve. It starts to open around 1 psi . I can put it into the air box but I think it’s better to vent it out. I will not get it in until Monday so I will keep all informed of my progress.Comment
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Yesterday I removed the vst vent orifice. No air was able to pass. I hooked it up to my air compressor and it took around 30 psi to push air through. My guess it should pass it through it easily if its vent?Comment
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doesn't sound right.
Yamaha used 3 (or was it 4?) different gizmos in the VST vent over the early years of the F225.
Don't know which you've got;
my F225 "D" has both a valve which opens <5 psi and an "orifice" which is never closedComment
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mine is a 03 f225 txrb I added the check valve Do those vst vent hoses move air in an out?Comment
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would it be better to just vent it without the check valve?Comment
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