Offshoreonly.com - 88 Baja stalls at high rpm

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new fuel filters, check fuel cond , check pump , fuel pressure

Quote:

Originally Posted by Budman II (Post 4439642)

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 did run the boat for about 5 minutes after adding in the fuel additive. I did not double check and make sure that the fuel in the float bowl had the additive in it, I just assumed. Definitely not hoping there is a chunk of piston flying around, but I will check compression. Thanks!

Quote:

Originally Posted by DBleil89 (Post 4439590)

Did you remove/ replace the filter that is in the carb behind where the fuel line connects? I had this same problem and that filter was clogged causing this same exact issue

I'd put my money on this scenario... Been there, done that.

Quote:

Originally Posted by offshore312 (Post 4439793)

I'd put my money on this scenario... Been there, done that.

I'd bet a beer on that one as well, but he should do what the rest of us do and dig in to clean the filter but instead ending up installing fuel injection and a mega blower, lol.

Quote:

Originally Posted by Baja Rooster (Post 4439870)

I'd bet a beer on that one as well, but he should do what the rest of us do and dig in to clean the filter but instead ending up installing fuel injection and a mega blower, lol.

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...

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.

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.

Quote:

Originally Posted by Griff (Post 4439652)

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.

I'm with Griff - when was the last tune up? Plugs, Wires, Cap and Rotor. An easy thing to check and change. I had a similar condition with missing at higher RPMs. Did a compression check that was fine, plugs looked good, pulled the cap to find all sorts of corrosion. Ran great after the tune up.

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....

Whenever I have had fuel bowls run dry from restriction, it would take extra cranking for it to restart.