2004 mercruiser 3.0 fuel pump sucking air?

[Fishfearme1174]

ok, so just finished attempting to replace fuel filter on this 2004 that has NEVER been changed - the fuel filter was in bad shape and the black painted bowl had a large sheet of paint inside the bowl floating around with very fine black paint debris - believe it or not the boat has been running good - just got around to changing this since i bought it. Any how NO LUCK getting new filter with spring installed in fuel pump bowl so installed a fuel/water separator and fuel bulb (which it needs anyway) i scrubbed the inside of the bowl very good with a wire brush until all traces of paint gone and only aluminum showing. Started her up and primed very quickly and started up. Only problem now is when I try to throttle it to raise rpm's it chokes out. What has happened? Did crap finally make it to the carbs? Or did the bowl not get torqued tight enough to the fuel pump allowing it to suck air under a greater demand (when I advance the throttle)? No leaks anywhere.

 

[Fishfearme1174]

Attwood water/fuel separator from Walmart

Is this ok to install in a 2004 mercruiser 3.0? I couldn't find the GPH rating. Having trouble keeping idle and raising rpms since installed.

 

[alldodge]

I think something is restricted, what that is need to do some testing. Installing a primer bulb in an enclosed engine compartment may not be the best idea, but just my opinion. I would suggest checking fuel pressure at the carb

 

[thumpar]

The fuel bulb is against USCG regulations.

 

[Fishfearme1174]

Filter in fuel pump did not get replaced. Way too difficult. There is now just an empty bowl for fuel pump and water fuel separator is only filter now. Issue with this? This couldn't cause it to be acting the way it is. Could it?

 

[Fishfearme1174]

Ok. But why? That is also where the water fuel separator got installed. Is that a problem also?

 

[alldodge]

Just noticed this thread needs to merge with this one you started with similar issues, there all fuel related
http://forums.iboats.com/forum/engi...608-attwood-water-fuel-separator-from-walmart

GA_Boater what do you think?

 

[thumpar]

The fuel bulbs are for outboards where there is no chance of blowing your boat up if/when it leaks. Also what kind of fuel line did you run? It needs to be A1 if it is flexible hose. I/Os can be an extreme explosion hazard if not done right.

 

[Fishfearme1174]

Don't matter why. your info is useless to my situation anyhow.

 

[alldodge]

There still the same topic. Filter removed, another added, having fuel related problems so all of these IMO should be part of your current issue.

My next suggestion is to test fuel pump pressure with a Tee inline between the pump and carb, between 4-7 psi

 

[Fishfearme1174]

The fuel bulbs are for outboards where there is no chance of blowing your boat up if/when it leaks. Also what kind of fuel line did you run? It needs to be A1 if it is flexible hose. I/Os can be an extreme explosion hazard if not done right.

I used the same line already in place. Did not add any new fuel line.

 

[alldodge]

Most all auto parts stores of HF, and most are under 20
http://www.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html

 

[Fishfearme1174]

Oh. Kick *****. Thx!!! So if pressure checks out ok. Would you say the carbs are next suspect?

 

[alldodge]

Oh. Kick *****. Thx!!! So if pressure checks out ok. Would you say the carbs are next suspect?

Depending on what is found. The other thread says it stalls when trying to throttle up it chokes (stalls) out. Need to find out if its flooding or no fuel, but both would lead toward the carb

 

[thumpar]

Don't matter why. your info is useless to my situation anyhow.

It does matter. You obviously have a fuel issue. You should not need a bulb to start your engine. Also you are risking lives.

 

[Fishfearme1174]

your info is priceless. Thx. I'd be more inclined to say it's flooding. Only reason is because it starts relatively easily. But after you throttle up and it stalls out its hard to start again. Like its flooded. Any adjustment I could make to the carbs at this point?

 

[alldodge]

Any adjustment I could make to the carbs at this point?

If it's flooding you should see fuel dripping down the throat of the carb. In this case need to check the float level with the needle and seat adjustment, and if there is crud in the valve area

 

[Fishfearme1174]

I already removed the bulb and it acts the same way. I'm going to test the pressure of the fuel
Line to the carb as one very generous member suggested to me. That should tell me a lot.

 

[Fishfearme1174]

I'd imagine if smell gas also in the engine compartment. In which I don't. Now I'm back to gas starvation.

 

[alldodge]

I'd imagine if smell gas also in the engine compartment. In which I don't. Now I'm back to gas starvation.

If it was just going down the carb the fuel smell may not be that much. If your using your blower during the starting procedure (very good idea) this to could remove fumes