90 hp merc 3 cyl problem!

[RIVERRUMMER 70]

HEY GUYS ........ BUDDY OF MINE WAS JUST TURNED AWAY BY A BIG TIME REPAIR FACILITY AFTER A MONTH AND A HALF TRYING TO FIX HIS MOTOR WITH NO RESULTS.....TOOK $200+ BUCKS FOR ADJ CARBS, NEW PLUGS,WIRES AND GAVE HIM HIS BOAT BACK AND SAID WE CANT FIGURE IT OUT SORRY. NO CREDIT NO FIX F.U. GOODBYE. I HAVE BEEN VERY BUSY SO HE HAD TO GO SOMEWHERE ELSE:mad: I RECOMENDED THIS FACILITY AND NOW FEEL LIKE AN A-HOLE .......SO HERE IS THE SYMPTOMS..........BOAT RUNS PERFECT UP TO 3500 ISH THEN STARTS ACTING LIKE ITS ON A REV LIMITER REALLY HARD AND WONT GO OVER 4000 R'S I HAVENT HAD A CHANCE TO DO ANYTHING WITH IT YET AS I AM UP TO MY EARS WITH A TON OF CRAP INCLUDING FLOOD PREP AGAIN ....:mad: TWICE THIS YEAR! JUST FINISHED CLEANING UP FROM THE FIRST ONE ! SOOOOOO... ANY IDEAS ON WERE TO START WHEN I DO GET A FREE MINUTE????:confused: THANX GUYS THIS GUY DESERVES SOME HELP AND HOPE WE CAN FIGURE THIS OUT BEFORE THE WEEKEND:thumbsup: R.R.

[CharlieB53]

First thing is check fuel supply. A motor will only pull up to the limited fuel supply. Either a weakened fuel pump, restriction in a line, or air leaking (sucking) into the system somewhere before the pump, any or a combination, will not keep the carbs full. Once the motor gets to that 'fuel limited' speed then it starts acting strange.

So disconnect a hose after the pump, crank the motor and see if it has a nice fat strong pulsed flow. Replace that section of hose with a clear hose, start and run the motor watching the clear hose for air bubbles indicating air sucking in.

REMEMBER, clear hose is NOT APPROVED for fuel use, it is only to be used as a very short term testing tool. Remove the clear hose as soon as finished testing.

Older hose can degrade the clear lining which can tear and 'flap' over, restricting flow. If hose is getting hard brittle or cracking, consider replacing it.

[RIVERRUMMER 70]

First thing is check fuel supply. A motor will only pull up to the limited fuel supply. Either a weakened fuel pump, restriction in a line, or air leaking (sucking) into the system somewhere before the pump, any or a combination, will not keep the carbs full. Once the motor gets to that 'fuel limited' speed then it starts acting strange.

So disconnect a hose after the pump, crank the motor and see if it has a nice fat strong pulsed flow. Replace that section of hose with a clear hose, start and run the motor watching the clear hose for air bubbles indicating air sucking in.

REMEMBER, clear hose is NOT APPROVED for fuel use, it is only to be used as a very short term testing tool. Remove the clear hose as soon as finished testing.

Older hose can degrade the clear lining which can tear and 'flap' over, restricting flow. If hose is getting hard brittle or cracking, consider replacing it.

THANX FOR THE REPLY CHARLIE.....SEEMS LIKE AN ELECTRICAL ISSUE MORE THAN FUEL .... THE SURGING IS WAY TO FAST AND CONSISTANT TO BE A FUEL PROBLEM. LIKE A REV LIMITER @3500 3700 ISH. I HAVE DELT WITH MANY A FUEL ISSUE BEFORE AND IT JUST DONT FIT THE SYMPTOMS. THIS THING WILL RUN FOR HOURS AND NOT MISS A BEAT UNDER 3500 ......... IT WILL HOLESHOT LIKE A RAPED APE UP TO 3500 THEN THE REV LIMITER TYPE SURGE HAPPENS. RUM RUM RUM RUM RUM RUM PERFECT TIMING NO STALL AND WHEN YIOU BACK OFF IT RECOVERS INSTANTLY AND RUNS LIKE A SEWING MACHINE. SOMONA BISH FARGIN ICEHOLE CRAP!:nonod:

[JWTjr.]

The 'ol timing light to each cylinder, degree & mark TDC flywheel for each cylinder and run it to 3500 (or when it drops), hook light to each cyl, watch light/spark & see what happens. If it's ignition it will show on the light.

[Superbender]

To me it sounds like a bad high speed winding in the stator,a simple check with a dva meter should help you out.

[RIVERRUMMER 70]

[QUOTE=Superbender;2498650]To me it sounds like a bad high speed winding in the stator,a simple check with a dva meter should help you out.[/QUOTE

THANKS FOR THE RESPONSE ......... NEVER HAD ONE ACT THIS WAY WITH A BAD STATOR.....USUALLY THEY FALL ON THEIR FACE AND THATS IT .....THIS IS WAY DIFF..... LIKE A REV LIMITER @3500 AND ITS HITTIN IT HARD . THE REPAIR FACILITY THAT HAD THE BOAT SAID THEY CK'D STATOR AND ACCORDING TO THEM ITS OK ....I HAVE NOT CK'D MYSELF TO BE SURE.......... BUT WILL WHEN HE BRINGS IT TO ME THIS WEEKEND!

[3springers26]

on the starboard side of the powerhead by the base gasket look for a 3x3 black box unplug the black/ yellow.. from it it's a rev limiter.. some had them some didn't based on the serial #, kurt

[JWTjr.]

love your avatar 3springers! Vintage Polaris SnoPro!

[King Dad]

What boat, what prop?? Are you/he over-propp'd? Remove the top, then the middle , then the lower carb drain plug, while catching the fuel on a clean rag so you can see what comes out. Then inspect each high speed jet while checking for ANY debris at all !!!!!!! Look close!!!!. Flush the carbs by squeezing the primer bulb and looking for anything that shouldn't be there. Re-assemble and go buy some Quicksilver Quickare fuel treatment made by Mercury. I'll bet your paycheck, it'll run like it hasn't in a while... or not!

[Capt.Insane-o]

:rolleyes:.................bad rev limiter

[Tcatrett]

If you don't find anything drop the main jets 2 sizes. I see this often. Don't know why but it works.