bill1

I have a 1990 292 with 454 Mags (385s). When accelerating above 40pmh (over 3200 RPM) the port side hesitates and loses revs with the engine wanting to go but seems like it is being held back). Up to around 3200 everything is good.

Is this a carb issue? Any thoughts would be appreciated.

Thanks,
Bill

bunky1957

Sounds like fuel delivery problem in the port engine.I would swap the carbs and see if the problem follows the carb or stays with the port engine.Maybe port fuel pump is bad or pickup in tank is restricted. You might also want to put a timing light on the motors to see if the timing is advancing with rpm at 3200.

jiffy292

iTrader: (1)

check the one way valves where the lines come out of the tank, change water seperator, if it has qjets check where the fuel line goes into carb theres a ball in there **** can get stuck in....if not i would suspect ignition have had same problems with the thunderbolt ignition

bill1

the answer is low compression in one cylinder (only acts up when the engine is warmed up).

awesome.

88242LS

uhg sorry to hear that

rer233

have you checked valve adjustment? worked on a friend's bayliner (ugh) this summer -engine seemed to hit a "wall" around 3000 rpm and missed under acceleration up to 3k. turned out no compression on 2 cyls. popped the covers, backed the rockers off to zero lash, tightened them down 1 turn, still no compression! then i tried adjusting them with the engine running (tighten down till engine misses, then back off till engine smoothed out.) buttoned everything back up, sea trialed the boat- 4400 rpm @wot. my friend still didn't trust it (nor did i.) called comp cams (they didn't have a real answer) and wound up putting a new set of their roller lifters in, tightened rockers down 3/4 turn past zero lash, and the boat's been fine since. bty- he's got a 350 vortec 2bbl (i know-ONLY in a bayliner.) hope this helps.

bill1

thanks very much for the suggestions.......had her out today and she was running fine again up to about 3200....didn't push her over that but strange anyways...........an addition to the winter to-do list.........