electric fuel pump tower of power 115hp

[drakocy]

1984, i like so many others lately have a no wot issue, it idles, when you dump the throttle you think hold on,,, then it bogs, pull it back to 1/3 throttle it idles ,, try it again,, dies,,, got a rebuild kit for the pump,,, something seemed different in the kit from what i had,, napa auto offered it a 9 bucks,,, tried pressure test at the top carb,, 3 lbs max when i hit the gas muffs,,,,, no vacum on the down side,,, can you put an electric fuel pump by the tank,,, i bought one, its 5 / 8 max psi,,,, it calls for 5 / 6 at wot,,, i do not think i will over pressure it and bend floats,,, this is something i was told would eliminate fuel pump doubts, can anyone help,,, the pum cost 46 bucks,, versus a mercury pump at 100,,, i have spark and went through some early test,,, im trying but stumped for now,,

 

[Chris1956]

Re: electric fuel pump tower of power 115hp

Adding an electric fuel pump to that motor is a risky proposition. If the fuel line ruptures, the pump will fill the boat with fuel, and it will find a source of ign.

Rebuild the mechanical fuel pump, make sure all the filters are clean and there are no air leaks in the fuel system, and go boating.

Hesitation when accelerating from idle is usually dirty carbs or misadjusted idle mixture. Bogging at high speed is usually lack of compression or a cylinder not firing. Weak fuel pump causes the motor to run at WOT for a few seconds before dropping to lower RPM for a few secondsm before reving back up to WOT.

 

[drakocy]

Re: electric fuel pump tower of power 115hp

tank is right at the back and i can eliminate rupture issues by having it outside for testing,,, mine will stay at the bog point for sometime,, it did not pick up and take off, it did not surge, not a miss fire either, ran 1 time did 47 mph on a trial rum,, this motor is sitting on a glass stream 15 boat,, i can almost eliminate prop sizing because that was not touched, just bogs and will eventually stall, for testing purposes does this make sense using the electric pump, thanks,,, i am one for being safe so thanks for the check up, i am just stumped,,, many boats to fix and not alot of time, as usual,,,

david

 

[usskydvr]

Re: electric fuel pump tower of power 115hp

Ok let's take this one step at a time. On a normal ( not cold or hot day) with the engine warmed up, can you slowly increase the throttle so you can get to running at 4500+ for an extended period say min 5 min? If so then you DO NOT have a fuel pump issue. As previously stated, when going from idle to WOT and you stumble, it is almost always the idle circuit adjustment. It takes patience and making equal ( on all carbs at the same time) 1/8 turn adjustments between tests (warm engine) to find the sweet spot.

 

[drakocy]

Re: electric fuel pump tower of power 115hp

left boat ramp, long no wake , so temp was nice, hammer the throttle and it just bogs, stays bogged till an almost stall, pull back throttle and it levels out, tried to feather the throttle , pumping slowly, etc, great at idling, and trolling, just no wot, so far, it did one day and found out bad stator, tested switch boxes, and all other electrical components, test rode again ran great then started to bog when i went to plane out, so i nursed it back to the dock,,, rebuilt fuel pump, let it sit with the fuel drained completly, now later in the season decided to try and remedy the problem again, looked close at the rebuild kit for the fuel pump, remembering something was amiss, i admit i did get the wrong fuel pum kit, but salvaged the best parts and reassembled, ordered right one today, i have 2 used ones also, i am just trying to sync the lincs and so on, the first one was off a bit, the throttle cam position.. and stop for carbs, took adjustment so far now came a downpoor, so i have to wait it out for a while, i had a mech, say about eliminating the fuel pump issue by using a electric pump for testing purposes, i can even mount it on the back but i do have all new quick silver line, and clamps, i am still up in the air,, todays fuels are a whole other issue and i try my best to keep it clean and mean, open to sugestions, and appreciate all coments,, it just seems there is alot of these same problems and i do not see much about trying this method,,, keep um coming,, thanks again

david

 

[usskydvr]

Re: electric fuel pump tower of power 115hp

So I know it can be a pain to have motor problems, but I think you are on the right path. Getting the CORRECT fuel pump rebuild kit. Taking the time to do the link and sync. You may also want to rebuild/check the carbs (crap plugging jets, incorrect float level, etc.) The only folks I know of that put on electric fuel pumps are HARD CORE big displacement O/B RACERS. Never heard of one on a stock engine.

 

[Fuzzytbay]

Re: electric fuel pump tower of power 115hp

Useing an electric fuel pump, even for testing, is just a way of trying to short cut proper troubleshooting. Since you have messed with the fuel pumps, already, get the correct kits and rebuild them. Once you have done this, move on the carbs, which are IMHO the problem. If its just the idle mixtrue, then you might be able to skip a link n sync, but that again depends upon how much "guess work fixing " you have already tried.

 

[j_martin]

Re: electric fuel pump tower of power 115hp

David,
The only thing you know for sure is your motor bogs when it should rip. You don't know exactly what component or components are at fault.

First things first, check the compression.

Then check it at idle. Is it hitting smoothly on all 6? If yes, that will rule out reeds and bleed lines.

Check the ignition system out per the charts in the book. Mostly make sure the stator, trigger, and coil signals are all good.

If you suspect fuel delivery problems, you can rig a temporary fuel pressure gauge. That way you will know if it's actually the problem, and be able to verify a fix when you find it. I have seen a V6 with about 7 distinct problems in the fuel system, all found and verified with a pressure gauge.

Like Chris said, it's more likely that the problem is in the carbs themselves, not the fuel pump. That's assuming that compression and ignition are up to par.

hope it helps
john
John

 

[dpsauto]

Re: electric fuel pump tower of power 115hp

david,
strange as i may sound i am battling the exact same problem at the moment. originally i was having an idling problem. it seemed that the motor was flooding and was hard to start. i rebuilt thecarbs and set the floats like the kits said. now it idles good but i have no WOT and it just wants to bog. after much trial and error i was able to get past the bog point and get it to open up and run until i went back to idle then it started all over again. i am getting plenty of fuel. it seems like something is not synced up right. it ran good at WOT until i went through the carbs so it has to be some minor adustment somewhere. if anybody has a good suggestion for me i would greatly appreciate it. or even if you think i am headed on the right path a little conformation would be good to.

 

[rheine]

Re: electric fuel pump tower of power 115hp

How about a failing fuel pump diaphragm, maybe a hole? Just a thought. But I should assume you got the rebuild in there.

 

[reynold460]

Re: electric fuel pump tower of power 115hp

having same exact issue have replaced switch boxes stator rebuilt fuel pump and still have same issue i am now convinced that it is some kind of carb issue have decided to repair myself one way or other boat repair shops take your boat have it for 3 weeks you get it back they say they fixed it and you take it on the water to find out you still have the same problem you had 3 weeks earlier unreal good boat mechanics are herd to come by