fuel pump or primer bulb?

[mickey117]

86 rude bogs down at full throttle,bulb keeps getting inflated then when pumped up and having someone keep pumping bulb while i'm throwing it in gear it will plan of and work fine till all of the sudden it'll bog back down.any ideas?

 

[tashasdaddy]

Re: fuel pump or primer bulb?

OK, let's see if we can work this out. is the bulb collaspeing, sucking in? or just getting soft. soft is normal while running, it's only hard for starting cold. someone has to pump it for you to put in gear. and it will plane off, but will bog down. did the person keep pumping? what year? a little more detailed discription would help. have you check spark, and compression. lets see if we can get it to run right.

 

[mickey117]

Re: fuel pump or primer bulb?

thanx it's a 1986 evinrude v4 90 hp.at first when i went to get and go it would bog.then we pumped the bulb and we got up.then after some drifting for fluke making many passes.then when it came time move on. i got up then all of the sudden it bogged down again.then we had a hard time starting it back up,then when i did finally get it started some smoke (which i thought to be from maybe being flooded?)THE bulb was soft which thought it had to be hard thanx.and i did not check plugs but i did just have motor worked on and they said it had great compression.i hope this is enough info to get us started once again thanx

 

[rickdb1boat]

Re: fuel pump or primer bulb?

If you can have someone pump the bulb continuously and it will run better, then more than likely it's a bad pump. It takes some rapid pumping on the bulb to keep it going though. It is normal for the bulb to be "Soft" when running, cause it has no purpose then. It just acts like part of the fuel line. Now if it is collapsing or getting sucked flat, that's another story. That would mean your fuel pump is working well enough to suck it flat. The only time the bulb will pump up firm is before you try to start it while not running or trying to start it...

 

[Big Keepers]

Re: fuel pump or primer bulb?

Assuming you have proper spark and compression, you need to check the vacuum and pressure of the fuel system. You can do this by getting a few T connectors, some fuel line and a vacuum and pressure gauge. Vacuum is read in inches of mercury and pressure in PSI. You would T in the vacuum gauge before the fuel pump and the pressure after the pump. Start the motor and see what you get. I use clear plastic hose so I can see the fuel and see if any air bubbles are in the line.

 

[tashasdaddy]

Re: fuel pump or primer bulb?

it sounds to be fuel delivery, disconnect the outlet hose on the fuel pump, connect a section of hose on to the fitting, now be ready to catch gas in a container. turn the engine over, you should get a really good spurts. if good has any work been done on the carbs, or the link & sinc? also are you using a built in tank, do you have a fuel/water separator? is vent clear and open on the fuel tank?

 

[mickey117]

Re: fuel pump or primer bulb?

thanx for all the suggestions.I was thumbing through my manual it mentioned that a kink in the fuel line would starve the system too.then when i looked i did have a kink or at the less the hose was pinched.I just don't want to go out just fixing the hose and have it not be it. what do you guys think?to answer your question about the linkage i just had the motor tuned up and the timing adjusted.and i'm running on 6 gal portable tanks.

 

[mickey117]

Re: fuel pump or primer bulb?

can someone help please.

 

[rickdb1boat]

Re: fuel pump or primer bulb?

Where was the kink? At the very least I believe it would restrict fuel flow, if not stop it all together. My thought is that when you had someone pump the bulb, it forced fuel past the kink and the motor ran. I would fix that situation and try it out...

 

[mickey117]

Re: fuel pump or primer bulb?

sounds like a plan thanx everyone.

 

[jammer]

Re: fuel pump or primer bulb?

OK, let's see if we can work this out. is the bulb collaspeing, sucking in? or just getting soft. soft is normal while running, it's only hard for starting cold. someone has to pump it for you to put in gear. and it will plane off, but will bog down. did the person keep pumping? what year? a little more detailed discription would help. have you check spark, and compression. lets see if we can get it to run right.

I would say a bad pump. My humble opinion.

 

[travllight]

Re: fuel pump or primer bulb?

I am working on a similar problem with an older Mercury 650 (65 hp) outboard. Like yours, my primer bulb doesn't want to firm up, and though I can get the motor to run at low speed, it sounds like it's struggling to get enough fuel. It's relatively easy to start and the rooster tail is fine.

I cleaned the spark plugs, replaced the fuel tank, and the fuel line. I took apart the filter unit (it wasn't clogged) and cleaned it out. I also tried setting the fuel tank at different angles. This didn't seem to help the problem. The hose inside the new tank had fallen off, so I put a different one on (about 3' long). Still, the primer bulb won't firm up when the line is connected to the motor. Disconnect the line at the motor, and the bulb firms up nicely.

The consensus here seems to be that the fuel pump is bad. I'll do some more work and post again when I know more.

 

[rickdb1boat]

Re: fuel pump or primer bulb?

If the bulb won't firm up, you may have a float sticking that's allowing fuel past the needle seat. After it runs, what do the spark plugs look like?

 

[mickey117]

Re: fuel pump or primer bulb?

if it is the pump.where could i find a new one.It's a fuel/oil pump (vro pump)or is the vro pump something different? I know i have one but not really sure if this is it or it's somewhere else like on my oil tank itself.anyway I'm getting side tracked where might I pick up a pump? (rick as far as the plugs go i didn't check after i ran it with the kink fixed,what are they going to tell me?)

 

[jammer]

Re: fuel pump or primer bulb?

if it is the pump.where could i find a new one.It's a fuel/oil pump (vro pump)or is the vro pump something different? I know i have one but not really sure if this is it or it's somewhere else like on my oil tank itself.anyway I'm getting side tracked where might I pick up a pump? (rick as far as the plugs go i didn't check after i ran it with the kink fixed,what are they going to tell me?)

Your vro pump is gas/oil. I got one locally from the dealer cost me 257. I've seen them on the internet for as low as 225

 

[Rich976usaf]

Re: fuel pump or primer bulb?

i would check the timing before changing the fuel pump. I changed a fuel pump with a similar problem and it didnot fix the problem...