Mercury FourStoke EFI 40HP 2005 Question

[Trakkat]

Hi!<br />I just bought a brand new 40HP Fourstroke EFI from Mercury. I ran it for the first time 2 weeks ago on the water for only half hour. I followed the break in instruction so I only pushed the throttle halfway up etc..<br /><br />Three days ago, I ran it again for almost 2 hours. But after 25 minutes, the engine started to act like if it was fuel starved. I had forgotten to open the vent on the gas tank. So I opened it.<br /><br />The thing is, after another 20 minutes it did the same thing, it did not stall but it revved down and up for a few times until I realeased the throttle completely. The outboard did this two times in the next hour until I got it back on the trailer.<br /><br />The folks from my boat shop examined the engine but they said everything was ok and that I should have turned off the engine, opened the vent, squeezed the primer bulb again and then restart the engine.<br /><br />I'm not sure I understand this. If the engine was running when I opened the vent, the fuel should still be pumped right?? Can someone explain me the principle of fuel primer bulb, fuel pump...<br /><br />I am a bit nervous about going back on the water again.

 

[oregonfish]

Re: Mercury FourStoke EFI 40HP 2005 Question

Primer bulb is like it says...primer. Once the engine is running, the fuel pump is what should be doing the work. If the engine boggs again, try pumping the bulb. If this improves the situation, it is likely a problem with the fuel pump. The vaccum may have blown a gasket or torn the diaphram in your pump.

 

[Trakkat]

Re: Mercury FourStoke EFI 40HP 2005 Question

I have tried what you said, squeezing the bulb when it boggs down. It does help, but couldn't it be the bulb? It feels very soft and I need to squeeze it at least 4 times before the engine return to normal operating speed... If the pump was damaged, I wouldnt be able to go at WOT, right?, but it's not the case. Even at mid throttle the engine finally die, it just take a bit longer.

 

[Nos4r2]

Re: Mercury FourStoke EFI 40HP 2005 Question

If the bulb pumps up til it's hard with the engine not running then the problem's not the bulb. <br /><br />In general a torn diaphragm won't necessarily stop fuel being pumped, it may just reduce the flow rate enough that it can't keep up with the engine demands

 

[Silvertip]

Re: Mercury FourStoke EFI 40HP 2005 Question

It's normal for the primer bulb to go soft after the engine has started. It should not be sucked flat however -- which indicates a restriction between the tank and bulb.

 

[Trakkat]

Re: Mercury FourStoke EFI 40HP 2005 Question

Hello again!<br /> My boat dealer finally replaced the fuel pump. Hopefully it will work. My concern is, they said that the fuel pump piston seized. This type of pump has a piston with a diaphragm and inside it there is two small plasic type valve. There is also a water inlet/outlet, wich I suppose is to cool the pump. What could cause such device to jam?? Overheat? If the metal piston increase in volume whent hot, the plastic casing wont so obiously it will jam again. Sure hope they checked if there was water flow to cool it off. Maybe just a bad pump after all.

 

[hrafnin]

Re: Mercury FourStoke EFI 40HP 2005 Question

i work merc in sweden and we changed about 50-60 fuelpumps each year 05 06, often its only when u go in full throttle for some time it shows, the pump usually delivers about 80% when broken this way and many people doesnt even know about it because they never go by full throttle =)

 

[Expidia]

Re: Mercury FourStoke EFI 40HP 2005 Question

I have the similar one but a 2007 that was delivered last month.

Once you get it squared away I can assure you that you will love this motor. The 2007 is just a little lighter in weight but pretty much the same motor.

The first one I bought from the dealer was a new 2006 30 hp and when I took it out the first time it would not go as fast as I expected. Some serial numbers were recalled for a throttle problem yet the dealer said mine was not one of them.

So I returned it to the dealer and had him order the 40 hp.

After he sold it to the next guy I saw the dealer a week later and he said Hey, you know that 30 hp you had. The guy had a problem where it would not go full throttle. I said how did you figure that out and he said he test drove it.

These dealers are funny on their meaning of customer service. I complained several times before I just said "take this motor back, I don't want it". Yet he never offered to test drive it, so he got it back!!!

If you're not comfortable with the repairs that were done, have them test drive it "on the water" not in a tank because they can't get the load that a boat puts on it in the tank.

You have a 3 year warranty. But you could have got a lemon too! I'd force them for a test drive on the water anyway because you don't want to have these problems arise while your on the water trying to out run a storm.

You bought a new motor so you wouldn't have to deal with all these problems. If it happens again, tell them you want "another" motor or a great deal on a newer motor since we are talking a 2005 here. Call in the regional guy if they won't appease your request. For 4 or 5 grand "Stand Your Ground" you should not have to deal with anymore fuel related issues . . .

My two cents

 

[Redneck Yacht Club]

Re: Mercury FourStoke EFI 40HP 2005 Question

Mercury PDI, is to test run the boat, the dealer failed to do that.
Am guessing that the dealership is landlocked? Not near water?
Throttle problem is a service buliten, just a stiffer plastic lever install.
Mercury dosen't pay for trips to the water

 

[EASTVIEW]

HI..I have a 40HP MERCURY..starts & idles perfect. in low gear runs fine , but when throttling up shimmy & shakes terrrible, buy in full throttle runs fine. when I throttle down its stalls out. It will start back up immediatly, the we start this process all over. t his is frustating as hell. Have replaced complete carb. system , still no change!..Any suggestions ??

 

[GA_Boater]

HI..I have a 40HP MERCURY..starts & idles perfect. in low gear runs fine , but when throttling up shimmy & shakes terrrible, buy in full throttle runs fine. when I throttle down its stalls out. It will start back up immediatly, the we start this process all over. t his is frustating as hell. Have replaced complete carb. system , still no change!..Any suggestions ??

Suggestion - Start a new thread. Your question is off topic (EFI motors have no carbs) and in a 12 year old dead thread. ID you motor cuz 40HP Mercury leaves a lot of models and years to choose from.

Closed.