88 Baja stalls at high rpm
05-16-2016, 03:15 PM
#12
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88 vintage 454 Mag probably has the Q-jet on it. Very possible that some deposits built up from fuel sitting in the carb. Almost all gas that is available today has at least 10% ethanol, which tends to invite moisture and cause oxidation in fuel systems. Did you use fuel stabilizer when it was winterized, and did you make sure that the stabilized fuel was fully drawn up into the float bowl of the carb?
I had a similar backfire on my boat about ten years ago, and thought it was a fuel delivery issue. Turns out I had a hole in an intake valve from a chunk of piston that lodged in there. Boat started up and idled fine, ran at cruising speed with no problem, but as soon as the secondaries started to open up it would backfire through the carb. Hopefully not your issue, but a sticking valve after the layup or a weak valvespring could also cause this. It would be revealed pretty quickly with a compression check before you start chasing other things like fuel pumps and ignition components.
I had a similar backfire on my boat about ten years ago, and thought it was a fuel delivery issue. Turns out I had a hole in an intake valve from a chunk of piston that lodged in there. Boat started up and idled fine, ran at cruising speed with no problem, but as soon as the secondaries started to open up it would backfire through the carb. Hopefully not your issue, but a sticking valve after the layup or a weak valvespring could also cause this. It would be revealed pretty quickly with a compression check before you start chasing other things like fuel pumps and ignition components.
05-16-2016, 07:28 PM
#13
05-17-2016, 05:54 AM
#15
well, when it happened to me I was dumb enough to install a new fuel pump. After all, the port engine was still pulling 5000 rpms... Starboard still had the same problem, miss at just less than 4000 rpms. I finally checked / changed the filter at the carb (I had the original quadra jets & that filter was filthy to say the least!) and shazzam! no more miss & burp, rpms went right back to 5000. Changed the port side carb filter also, since I was in the neighborhood. It wasn't as bad but certainly worth doing. I've been changing them at the start of the season every since, and carry spares...
Last edited by offshore312; 05-17-2016 at 05:56 AM.
05-17-2016, 09:08 AM
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I checked the filter at the carb yesterday and it was super clean. So I'm not thinking it was a fuel issue. Could there be some damage or something to the carb itself that may be causing this? Someone local mentioned possibly an issue with the float.
05-17-2016, 09:14 AM
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Yes just remove the file line and then unscrew the piece that the line threads into. There is a brass or plastic filter there. Take that to your marine parts store and get a new one. Then run the boat.
I had the brass one it looked clean but I replaced it and that made it run perfect. You could have a carb issue but usually with the slow filter it let's the bowls fill and the motor run until you want more fuel then it can flow. Even through it looks good I would replace it since it's cheap and then see how the boat runs.
I had the brass one it looked clean but I replaced it and that made it run perfect. You could have a carb issue but usually with the slow filter it let's the bowls fill and the motor run until you want more fuel then it can flow. Even through it looks good I would replace it since it's cheap and then see how the boat runs.
Last edited by DBleil89; 05-17-2016 at 09:18 AM. Reason: Adding info
05-17-2016, 11:06 AM
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One of my engines was doing a similar thing a few years ago. Inspected cap and rotor and had lots of corrosion.
It was fine under a light load at a 3500rpm cruise speed. Push the sticks forward quickly and it would stall.
Push them slow and it would start to miss around 4000 rpms.
Cap and rotor replaced and all was good.
It was fine under a light load at a 3500rpm cruise speed. Push the sticks forward quickly and it would stall.
Push them slow and it would start to miss around 4000 rpms.
Cap and rotor replaced and all was good.
Last edited by bohmi; 05-17-2016 at 11:13 AM.
05-17-2016, 11:08 AM
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Long time lurker and have gotten great information from this site. Just wanted to create an account and post to try and contribute. The information I've gotten searching here has been incredible. Years of other's experience to pull from....
05-17-2016, 12:54 PM
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Whenever I have had fuel bowls run dry from restriction, it would take extra cranking for it to restart.
