Took boat out today to test my new wiring with my acr setup. All is good there but I found another problem. I was running my aux tank the other day fishing an didnt have a problem but today I switched the valve to my main tank an it ran fine for a lil while then both engines started shutting down. Flipped valves back to aux tank an it ran fine. Tried main tank again an same problem. So I have a fuel delivery problem on my main tank. Where should I start?
Main fuel tank problem
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SeanC
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Try running with the fuel cap loose on the main tank. May be a blocked vent and a vacuum is forming and starving the engines.
That's what I was thinking was the problem. I'll try that next time I take it out. Thanks
could be a blocked check valve at the tank/fuel pickup tube.
Where would the check valve be at? I see the two pickups but dont see a check valve anywhere. It's just strange that both motors died out at the exact same time which would tell me the tank is not venting. I see where the vent an fill is for the aux tank but for the main tank the fill an vent line look like they go to the front of the boat. Does any one know how to access the main tank fill an vent
OK. It could be a clogged vent.
I assume that you have two valves to select tanks, one for each motor. If so try setting one motor to aux and the other to main and see what happens. Than reverse the valves and see how that works As suggested run with the cap off to see if that helps. The more full the tank, the quicker a clogged vent will cause fuel flow issues.
If you have a separate tank vent ( you will see it on the side of the hull, take a look to see if the opening is plugged. If you have a combo fill/vent arrangement, trouble shooting is a bit trickier , There is a check valve in the cap. I don't know your boat's history but if this problem was there all along and you just didn't get to test for it, it is possible that someone replaced the filler cap with the incorrect model ( that is a non vented cap screwed into a combo fill/vent fitting. .
There are other causes for fuel starvation but in most cases, the motors don't die at the exact same time since the causes usually don't occur at the same time ( e.g, air leak, bad valves, stuck anti-siphon valve). If the vent line had been replaced and was run with a low loop, it can collect liquid gas or water in that loop. The suction of the motors may not be strong enough to clear the vent live and starvation can occur. In that case, the open gas cap should tell you that there is a vent issue
One final comment on the fill up. If there is a venting issue, when you fill the tank, the nozzle may shut off over and over, making you think the tank is full but it may not have been. If the fuel level is low, by adjusting the hull angle may make the problem show up or go away. On plane, the tank is more level and the overall gas height near the pickup is shallower than when the bow is up as when displacing.
I assume that you have two valves to select tanks, one for each motor. If so try setting one motor to aux and the other to main and see what happens. Than reverse the valves and see how that works As suggested run with the cap off to see if that helps. The more full the tank, the quicker a clogged vent will cause fuel flow issues.
If you have a separate tank vent ( you will see it on the side of the hull, take a look to see if the opening is plugged. If you have a combo fill/vent arrangement, trouble shooting is a bit trickier , There is a check valve in the cap. I don't know your boat's history but if this problem was there all along and you just didn't get to test for it, it is possible that someone replaced the filler cap with the incorrect model ( that is a non vented cap screwed into a combo fill/vent fitting. .
There are other causes for fuel starvation but in most cases, the motors don't die at the exact same time since the causes usually don't occur at the same time ( e.g, air leak, bad valves, stuck anti-siphon valve). If the vent line had been replaced and was run with a low loop, it can collect liquid gas or water in that loop. The suction of the motors may not be strong enough to clear the vent live and starvation can occur. In that case, the open gas cap should tell you that there is a vent issue
One final comment on the fill up. If there is a venting issue, when you fill the tank, the nozzle may shut off over and over, making you think the tank is full but it may not have been. If the fuel level is low, by adjusting the hull angle may make the problem show up or go away. On plane, the tank is more level and the overall gas height near the pickup is shallower than when the bow is up as when displacing.
According to the fuel gauge the tank is 3/4 full, I'm 100 percent positive it's not low on fuel. I'll try what you sugested
Just took vent line off and blew through it an there was no restriction at all so that's not it. Gona check the two pick up lines in the tank or the gas cap but I took gas cap apart an tested it an all seams fine there
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Sticky anti-siphon valve?? Closing off fuel flow?
Located on fuel line coming out of tank, the barb that the fuel line attaches to.
Located on fuel line coming out of tank, the barb that the fuel line attaches to.
After you switched to main tank, started up and went for a run, how much time elapsed before the engines died?
After they dies, did you try to restart? Did you give the primer bulbs a squeeze to see if they were firm, collapsed or in between?.
Can you explain how many valves you have to select tanks? I am not familiar with that plumbing. Is it possible that you were initially running on the main tank and switched to aux . If so, perhaps the aux tank has issues.
This is all guessing on my part but what else am I to do? It's too hot to be outside
After they dies, did you try to restart? Did you give the primer bulbs a squeeze to see if they were firm, collapsed or in between?.
Can you explain how many valves you have to select tanks? I am not familiar with that plumbing. Is it possible that you were initially running on the main tank and switched to aux . If so, perhaps the aux tank has issues.
This is all guessing on my part but what else am I to do? It's too hot to be outside
I checked that an I do not have a anti siphon valve, previous owner must have taken it off an put a regular hose barn in its place
It actually took a while before I had the issue I would say maybe 10 min. I was heading in one direction an turned around an went straight for a minute then it happened. I was able to restart an go again that time it didnt take as long for it to happen. It's not the aux tank I'm pretty sure cuz I went offshore two weeks ago an ran on my aux tank. I have never been able to tighten up my primer bulbs, I can squeeze them for hours an they would never get hard, why is this?? I have two valves one on each side of the boat, I took them off an tested them an they are both working correctly.After you switched to main tank, started up and went for a run, how much time elapsed before the engines died?
After they dies, did you try to restart? Did you give the primer bulbs a squeeze to see if they were firm, collapsed or in between?.
Can you explain how many valves you have to select tanks? I am not familiar with that plumbing. Is it possible that you were initially running on the main tank and switched to aux . If so, perhaps the aux tank has issues.
This is all guessing on my part but what else am I to do? It's too hot to be outside
Just got back from river to test boat out again an I idled out the creek which takes about 5 minutes to get to river. Got out to river and punched it rpm's went up then she started begging again same problem. Cut motors off an primed bulbs an fired them up an tried again. Ran boat for a solid 30 minutes not a single problem!! Guess it's fixed an I didnt even do anything, guessing there was a air bubble or a piece of trash who knows but it's working now!
If it is a piece of trash in the tank, it has to be big enough to block both pickups assuming that both motors die at the same time give or take a few seconds.
I am pretty sure the problem will happen again unfortunately.
The primer bulbs may not get firm for a few reasons: The check valves in the bulb is bad, There is an air leak between the primer bulb and the tank, there is no gas in the tank or there is a fuel leak after the primer but you would see/smell that.
The fact that you can go slow without issues but stall when you speed up (punch it as you say) still sounds like a fuel starvation issue due to low flow perhaps from a venting issue or junk in the tank. The key fact is that both motors die out at the same time and there aren't a lot of common problems that affect both motors at the same time other than no gas, blockage of both pickups or vent issue.
I do not suspect anti-siphon valve but should point out that many of those look exactly like NPT to barbed fittings. It isn't always obvious that you have the anti-siphon valves.
I am pretty sure the problem will happen again unfortunately.
The primer bulbs may not get firm for a few reasons: The check valves in the bulb is bad, There is an air leak between the primer bulb and the tank, there is no gas in the tank or there is a fuel leak after the primer but you would see/smell that.
The fact that you can go slow without issues but stall when you speed up (punch it as you say) still sounds like a fuel starvation issue due to low flow perhaps from a venting issue or junk in the tank. The key fact is that both motors die out at the same time and there aren't a lot of common problems that affect both motors at the same time other than no gas, blockage of both pickups or vent issue.
I do not suspect anti-siphon valve but should point out that many of those look exactly like NPT to barbed fittings. It isn't always obvious that you have the anti-siphon valves.