Walleye4Days
Contributing Member
Hi guys, just bought a new to me 1984 Sportcraft 250 Hardtop with a 305 in it attached to a 280-PT Duoprop. 800hrs on the engine/outdrive, and decent maintenance on it thus far. I know the boat has good compression and is a great runner, as I used the boat many times this season with my buddy and just finally got around to buying it from him.
I apologize for the lengthy info, I just like to be as thorough as possible when describing problems, and thank you very much for anyone able to help shed some light on these questions I have.
At the beginning of the season, the boat was running a little rough here and there, so we changed the hei distributor because the old one was whooped/had broken advance springs and signs of potential humidity intrusion/et cetera. Then, about a month ago we kept getting stranded randomly as the engine would randomly cut out Sometimes under way, sometimes during idle, and sometimes wouldn't crank back up with no rhyme or reason to any of it. We assumed fuel because, after all, the entire ignition was brand new along with fresh 8mo old high end wires and plugs.
So, a local marina buddy rebuilt the quadrajet 4bbl carb for me, and overall the boat ran great after all that to 4400rpm at wot like usual and we assumed the problem must've been the carb. But, then it started doing it again only two trips later. So, we hunted and hunted and narrowed down the problem to no spark; the module in the distributor was bad at only a month old (US made Marine flamethrower) as they used a gnats ass amount of heat sync paste and barely any of the modules underside was covered. So we realized it got heat stroke and was crapping out.
So, we replaced the module with a GM module we had from one of our other distributors, and the boat decided to run great again in the slip, but we had already bought a new Carter marine fuel pump in anticipation of it being a fuel issue so we put it in too before going out on a test run. Well, she started up, idled, and revved amazing in the slip after the fuel pump swap too, so we then double checked timing as precaution and timing was good so we planned out a test run. But, when getting out of Lorain Harbor (Lake Erie/Ohio) and on to planing, we're only getting 2500-2800rpms underway at around 1/2throttle or so, and only gain to 3000rpms or so past 1/2 way all the way up to wot.. So, in short, top end is all of a sudden not there since changing the fuel pump and putting in the new module. So, obviously it leads me to either the module not keeping up (I don't know if that is even possible because I'm not ENTIRELY sure exactly how the module operates in depth) or the fuel pump somehow.
Which leads me to my questions: I noticed that there was no spacer inbetween the fuel pump and block when installed by my buddy, and the old pump didn't have a spacer there either (at least I don't think I seen one on it, but I can't be 100% sure). But, the new fuel pump is slightly different in shape/depth and it came with two thin gaskets in the box, which leads me to wonder if there's supposed to be a spacer inbetween them on this AQ225D (305 GM engine), as I know other engines have a spacer inbetween the pump and block often. It idles great, revs up high heat great while in neutral, but doesn't get past around 2800-3000rpm under load. Would absence of a spacer cause that kind of potential behavior IF that'd be the culprit (ie- does it change pressure or volume in its absence)? Or, is it something to do with the GM module we swapped into the flamethrower distributor not being able to keep up with the advance of the distributor? I'm just kinda at a loss here and have no idea what to target.
Ran great with the new distributor until the module in it crapped out. Then swapped in a module from another distributor and changed out the fuel pump and now no top end rpms when under load.
Thanks for reading my essay, and any insight will surely be appreciated because my Seloc manual has nothing regarding these answers in it.
I apologize for the lengthy info, I just like to be as thorough as possible when describing problems, and thank you very much for anyone able to help shed some light on these questions I have.
At the beginning of the season, the boat was running a little rough here and there, so we changed the hei distributor because the old one was whooped/had broken advance springs and signs of potential humidity intrusion/et cetera. Then, about a month ago we kept getting stranded randomly as the engine would randomly cut out Sometimes under way, sometimes during idle, and sometimes wouldn't crank back up with no rhyme or reason to any of it. We assumed fuel because, after all, the entire ignition was brand new along with fresh 8mo old high end wires and plugs.
So, a local marina buddy rebuilt the quadrajet 4bbl carb for me, and overall the boat ran great after all that to 4400rpm at wot like usual and we assumed the problem must've been the carb. But, then it started doing it again only two trips later. So, we hunted and hunted and narrowed down the problem to no spark; the module in the distributor was bad at only a month old (US made Marine flamethrower) as they used a gnats ass amount of heat sync paste and barely any of the modules underside was covered. So we realized it got heat stroke and was crapping out.
So, we replaced the module with a GM module we had from one of our other distributors, and the boat decided to run great again in the slip, but we had already bought a new Carter marine fuel pump in anticipation of it being a fuel issue so we put it in too before going out on a test run. Well, she started up, idled, and revved amazing in the slip after the fuel pump swap too, so we then double checked timing as precaution and timing was good so we planned out a test run. But, when getting out of Lorain Harbor (Lake Erie/Ohio) and on to planing, we're only getting 2500-2800rpms underway at around 1/2throttle or so, and only gain to 3000rpms or so past 1/2 way all the way up to wot.. So, in short, top end is all of a sudden not there since changing the fuel pump and putting in the new module. So, obviously it leads me to either the module not keeping up (I don't know if that is even possible because I'm not ENTIRELY sure exactly how the module operates in depth) or the fuel pump somehow.
Which leads me to my questions: I noticed that there was no spacer inbetween the fuel pump and block when installed by my buddy, and the old pump didn't have a spacer there either (at least I don't think I seen one on it, but I can't be 100% sure). But, the new fuel pump is slightly different in shape/depth and it came with two thin gaskets in the box, which leads me to wonder if there's supposed to be a spacer inbetween them on this AQ225D (305 GM engine), as I know other engines have a spacer inbetween the pump and block often. It idles great, revs up high heat great while in neutral, but doesn't get past around 2800-3000rpm under load. Would absence of a spacer cause that kind of potential behavior IF that'd be the culprit (ie- does it change pressure or volume in its absence)? Or, is it something to do with the GM module we swapped into the flamethrower distributor not being able to keep up with the advance of the distributor? I'm just kinda at a loss here and have no idea what to target.
Ran great with the new distributor until the module in it crapped out. Then swapped in a module from another distributor and changed out the fuel pump and now no top end rpms when under load.
Thanks for reading my essay, and any insight will surely be appreciated because my Seloc manual has nothing regarding these answers in it.
