rmcderm313
Regular Contributor
Hi Folks need some help
The motor is a 2006 Mercury 9.9 4-Stroke Serial #0R152540
The issue is the motor will start easily and idle without issue. As soon as I start to throttle up, I am able to only advance a small bit and then the motor will stall. It starts up again easily but exhibits the same behavior each time. This happens with both the prop engaged as well as in "throttle only" mode by pressing the button on the side of the motor.
The motor has been running great since I re-commissioned it about 3 weeks ago. It was running great yesterday morning. I filled up the tank with gas at a marine gas station (suspect?) and about 10 minutes later it died at full throttle and this behavior started.
Interesting note, with the choke pulled out the motor runs fine, or at least it advances fine without exhibiting this issue. I'm sure it's running rich but it runs fine all the same. So I'm thinking that might rule out a spark issue as well as any fuel line issues (why would fuel be delivered efficiently with the choke out if there was an issue with the lines or spark plugs). But I'm interested in other opinions on that note.
Over the winter I completely replace the carb (which is not to say the carb couldn’t be the problem, but it is recently new). Obviously the timing of this issue makes me suspect an issue with the fuel I got from the gas station, but again if the fuel was the issue, why would it seem to be good when the choke is pulled out? I would assume that bad fuel is bad fuel and would cause issues in both scenarios.
I'm going to replace the in-line fuel filter just to be sure but again I don't think that would be the issue for the same reason as above. So aside from closing the butterfly on the carb to force a richer mixture, what else happens when the choke is out that might help me understand this issue? Would the richer mixture caused by the choke being pulled out, be enough to mask other issues with the fuel, fuel pump, spark plugs or fuel line?
I'm leaning towards this being some sort of clog in a high speed jet in the carb. I think I remember being told that as the throttle advances the carb uses different jets to deliver fuel. BUT, if that is the cause, why wouldn't I be seeing some effect of this when the choke is out?
I made a video that shows the behavior that I'm uploading to YouTube now, and will post as soon as it's done. I didn't make a video of it running with the choke pulled out, but the motor advances perfectly in "throttle only" mode with the choke pulled out. No stutters or hesitation at all.
Thanks in advance for your help. Any tips to troubleshooting this issue would be greatly appreciated.
Oh and one other question for the meantime. I had to leave this boat at a friends dock. If I can run it with the throttle out to get it back home, would that damage the motor? Advised? Ill-advised?
Thanks.
Rob
The motor is a 2006 Mercury 9.9 4-Stroke Serial #0R152540
The issue is the motor will start easily and idle without issue. As soon as I start to throttle up, I am able to only advance a small bit and then the motor will stall. It starts up again easily but exhibits the same behavior each time. This happens with both the prop engaged as well as in "throttle only" mode by pressing the button on the side of the motor.
The motor has been running great since I re-commissioned it about 3 weeks ago. It was running great yesterday morning. I filled up the tank with gas at a marine gas station (suspect?) and about 10 minutes later it died at full throttle and this behavior started.
Interesting note, with the choke pulled out the motor runs fine, or at least it advances fine without exhibiting this issue. I'm sure it's running rich but it runs fine all the same. So I'm thinking that might rule out a spark issue as well as any fuel line issues (why would fuel be delivered efficiently with the choke out if there was an issue with the lines or spark plugs). But I'm interested in other opinions on that note.
Over the winter I completely replace the carb (which is not to say the carb couldn’t be the problem, but it is recently new). Obviously the timing of this issue makes me suspect an issue with the fuel I got from the gas station, but again if the fuel was the issue, why would it seem to be good when the choke is pulled out? I would assume that bad fuel is bad fuel and would cause issues in both scenarios.
I'm going to replace the in-line fuel filter just to be sure but again I don't think that would be the issue for the same reason as above. So aside from closing the butterfly on the carb to force a richer mixture, what else happens when the choke is out that might help me understand this issue? Would the richer mixture caused by the choke being pulled out, be enough to mask other issues with the fuel, fuel pump, spark plugs or fuel line?
I'm leaning towards this being some sort of clog in a high speed jet in the carb. I think I remember being told that as the throttle advances the carb uses different jets to deliver fuel. BUT, if that is the cause, why wouldn't I be seeing some effect of this when the choke is out?
I made a video that shows the behavior that I'm uploading to YouTube now, and will post as soon as it's done. I didn't make a video of it running with the choke pulled out, but the motor advances perfectly in "throttle only" mode with the choke pulled out. No stutters or hesitation at all.
Thanks in advance for your help. Any tips to troubleshooting this issue would be greatly appreciated.
Oh and one other question for the meantime. I had to leave this boat at a friends dock. If I can run it with the throttle out to get it back home, would that damage the motor? Advised? Ill-advised?
Thanks.
Rob