fuel pump or (spark plug wire)

[leafs]

i have a 1974 johnson 70hp<br />compression 125 on all 3,new spark plugs,changed cracked gas lines from fuel pump to carbs new primer bulb,just got the engine timed. when i take the boat out i pump the primer bulb it gets a little firm but not hard and it will not stay hard i can not see any leaks on the gas line or bulb.when i first start off the motor revs up while i am opening up the throttle for a few seconds and then dies down to a low rev .and stays at that low rev even if you have it wide open. then if you shutt the engine off and restart it it does the same thing revs up and then down. the engine does not miss or run ruff when all this is going on . is there anything i could check out.i bought this boat a few weeks back and my kids want to go tubbing

 

[sloopy]

Re: fuel pump or (spark plug wire)

replace the primer ball

 

[leafs]

Re: fuel pump or (spark plug wire)

it is new ,the old one did the the same think.we also tried pumping it while driving it made no difference on the way it reved

 

[sloopy]

Re: fuel pump or (spark plug wire)

what about the fuel line?

 

[leafs]

Re: fuel pump or (spark plug wire)

i did not replace the fuel line it is still soft and it is not leaking as far as i can tell (dry)

 

[sloopy]

Re: fuel pump or (spark plug wire)

replace it just to be safe

 

[leafs]

Re: fuel pump or (spark plug wire)

any ideas of want else i could look for ,i will replace the fuel line tommorrow

 

[sloopy]

Re: fuel pump or (spark plug wire)

nope thats the end of my suggestions

 

[sloopy]

Re: fuel pump or (spark plug wire)

nope thats the end of my suggestions

 

[brother chris]

Re: fuel pump or (spark plug wire)

I agree with Sloopy, replace the line and all should be fine.

 

[leafs]

Re: fuel pump or (spark plug wire)

would the gas line not be leaking somewear if it is faulty

 

[leafs]

Re: fuel pump or (spark plug wire)

any other ideas

 

[sloopy]

Re: fuel pump or (spark plug wire)

yes the gas line could be leaking drawing in air

 

[leafs]

Re: fuel pump or (spark plug wire)

well a put a new complete gas line on with primer pump,still doing the same thing.i was toll by a boat mech that the bulb will go soft if the fuel pump is not working right. does this sound right,is there also other things that could cause my problem

 

[leafs]

Re: fuel pump or (spark plug wire)

i changed the fuel pump today,how much fuel should come out of the pump with motor running there is a steady flow of gas but a mech said it should shoot a couple of feet,mine does not shoot that far. does anyone know about the gas flow from these pumps

 

[Reel Appeal]

Re: fuel pump or (spark plug wire)

Hi Leafs,<br /> I had the same engine a few years back.<br />I would take a look at those carbs.First,on the outside,make sure those drain screws on the carb bowls are tight and not dripping.Prime the bulb.Do the carbs look wet on the outside/bottom?After excluding this you said the primer bulb won't get hard...Take a look inside those carbs.Are any or all the floats sTuck open?Are the needle valves in good shape?TIGHT SEAL? If the needle valves inside the carbs are worn that would explain your soft primer bulb.<br />Back to the fuel line.Do you have it hooked up correctly so the primer bulb is nearest the gas tank?There may be an arrow on the primer bulb.Is it pointing towards the motor?Also,when you prime it,do you hear air coming out at either end of the fuel line?Maybe it's not connected all the way on,on one end.

 

[leafs]

Re: fuel pump or (spark plug wire)

yes the primer bulb is close to the gas tank,and it is dark here so i will check tomorrow about if the bottom of the carbs are wet i think i noticed that the bottom two looked a little wet,if they are do they have to be rebuildt. i suppose there is no way on checking the floats with out taking the whole carb apart

 

[leafs]

Re: fuel pump or (spark plug wire)

?

 

[leafs]

Re: fuel pump or (spark plug wire)

changed lines to carbs,new gas line 2 primer bulb,<br />new fuel pump,primer bulb still does not remain hard,any ideas

 

[Solittle]

Re: fuel pump or (spark plug wire)

I'm going to take a guess. You should have two fuel filters, one on the engine and one on the tank. Check both for crud.<br /><br />If that dosen't do it squeeze the bulb and start as you described - when it starts to slow down, squeeze the bulb. If it picks up my guess is that you have an air leak in the fuel delivery system. You did not mention if you changed the fuel line connectors. They have a small "O" ring inside and when old or chiped they will leak air giving the symptoms you describe.