Engine bogging down, very little power

[Emeraldsnake]

Transom serial number is OL287387. Drive seal number is OL406238, Engine number is 0L097202. I have a Bayliner 2052LS Capri. 1999 3.0l GM engine with Mercruiser Alpha 1 Gen 2. On other threads I have explained various problems that I have had. Finally this weekend I had a trip out. But I could only trundle along at around 5 knots. Opening the throttle caused the engine to bog down and die. Any ideas? Carb is fine, inline fuel filter at carb end is fine. I'm thinking its just now tweaking the fuel mixture needle? Engine ticks over sweet at 685rpm. Goes into gear lovely etc. could it be accelerator pump, or fuel pump filter? Just have no power when I engage the drive. Revs okay with just throttle. Help me with the final peice of the puzzle. Thanks in advance. Mike.

 

[alldodge]

Re: Engine bogging down, very little power

No on fuel mixture, these are only for idle.
Accelerator pump if malfuctioning will cause it to stumble but if given gass slowley it will come up to speed.
Fuel pump is a possibility and if your filter is clogged this can also cause your issue.
Reving in netural uses next to no gas
When was the filter replaced?
When you push the throttle full open does the carb open fully?

 

[camalot]

Re: Engine bogging down, very little power

It could be many things!!

How many turns out are you on the idle mixture?
Looking down the carb from the top and getting someone to throttle up quick do you see two jets of gas.
Is the float height correct?
Does it pop in the carb when you throttle up?

It does sound like fueling...................but you said the card is fine.

 

[Emeraldsnake]

Re: Engine bogging down, very little power

I will remove and clamp the fuel lines, and check out the fuel filter at the base of the fuel pump. Anyone know the part number for the fuel filter I need if it does need replacing? Although a good squirt of cleaner may do the trick....will let you know. Thanks lads.

 

[Emeraldsnake]

Fuel pump filter removal and replacement

Fuel pump filter removal and replacement

Hi. I have a Bayliner 2052LS Capri with a 3.0 mercruiser. 1999. Drive seal number is OL406238, Engine number is 0L097202. Transom serial number which is OL287387. I am wondering if anyone can post a link or an exploded view of my fuel pump. I think I have a blocked or dirty fuel filter in it, and would like to clean or replace it. Engine bogs down really bad when moving. Only getting 5 knots and an almost dead engine. Filter at the top by the carb is clean. Just want to safety check the lower one. Thanks. Mike.

 

[Scott Danforth]

Re: Engine bogging down, very little power

with the engine off, look into the carb while someone gives it throttle. if you do not see two nice streams of fuel squiring into the carb just above the throttle plate, then you have an accelerator pump issue.

 

[alldodge]

Re: Engine bogging down, very little power

Go here and enter your serial number: Once in the catalog the top right is a dropdown menu and will supply you with all the exploided views.

Parts Catalog | Mercury Marine

 

[Emeraldsnake]

Re: Engine bogging down, very little power

Great stuff. I have ordered my fuel filter kit. Will let you know how it goes. Can I assume that it is (bare with me) clamp one fuel line, the one going up to the carb, undo the bottom nut and release catch, drop the old filter and gasket out, then opposite with new filter and gasket to put back together? Never done it, just want to be sure. Thanks. Mike.

 

[achris]

Re: Engine bogging down, very little power

One of my favourite diagnotic tools is clear plastic tubing. Really cheap and very effective. Dead simple to use and gives instant results.

Mike, you're problem does sound like fuel. But you appear to have checked all the obvious things, statically. Here's a quick and easy check dynamically. Insert a short section of the clear tube in the fuel line, preferably just before the carb.

Run the engine. when you have your problem, just look at the tube. If you see bubbles, your fuel pump is sucking air from somewhere in the fuel delivery system. If you don' t see bubbles, you can be pretty sure the system is air tight.

Remember, diagnostics is as much about eliminating things as it is about finding a fault.

The only other thing I would do is to tee a vacuum gauge into the fuel line immediately before the fuel pump. You need to see less than 2" of Mercury.

If you pass both these (quick and easy) tests you KNOW the fuel delivery system is good, and you can move onto something else with confidence.

HTH..

Chris......

 

[achris]

Re: Engine bogging down, very little power

Great stuff. I have ordered my fuel filter kit. Will let you know how it goes. Can I assume that it is (bare with me) clamp one fuel line, the one going up to the carb, undo the bottom nut and release catch, drop the old filter and gasket out, then opposite with new filter and gasket to put back together? Never done it, just want to be sure. Thanks. Mike.

It may be difficult to clamp the line from the fuel pump to the carb, since it should be a steel tube. Clamp the rubber line coming in from the tank (just before the pump) then proceed as you planned. I would drop a rag in the bilge below the pump to catch any fuel that spills (and it will :facepalm: .... Just take your time with the pump cover gasket. Don't want to introduce a leak...

Chris.....

 

[Emeraldsnake]

Re: Engine bogging down, very little power

My saviour! Hello again Chris. No, I don't want to add a leak to add to my despair! :facepalm: Love the clear tube idea. A simple, effective, commen sense approach. Love it. Will let you know how it goes. All the best. Mike.

 

[Emeraldsnake]

Re: Engine bogging down, very little power

And thanks for the promotion......seaman apprentice.....about right!

 

[Bondo]

Re: Engine bogging down, very little power

And thanks for the promotion......seaman apprentice.....about right!

Ayuh,.... Ranks are automatic, accordin' to Post Count,.... The more posts, the higher the rank,...

At 10,000 posts, ya get to pick yer own rank,...

 

[Volphin]

Re: Engine bogging down, very little power

I give Mike serious quality points for using the word "trundle" in a post correctly. That made me smile!

 

[achris]

Re: Engine bogging down, very little power

At 10,000 posts, ya get to pick yer own rank,...

Yep, still working on that... any suggestions?

 

[Emeraldsnake]

Re: Engine bogging down, very little power

Erm...thanks Bondo, I realised that. It was tongue in cheek....

 

[Emeraldsnake]

Re: Engine bogging down, very little power

Anyway, back to subject. I got a friend to throttle whilst I looked down the carb. I get two lovely jets of fuel for a few pumps,then they sort of die off. I start the engine, (with the flame arrester off...yeah... I know), and see two good jets when it's revved. But after a few more goes, it turns to a spray,then a fine mist and then almost nothing. I took her out around the harbour, trundle was fine (that's for you Volphin!), but opening her up bogged her down again. Pumping the throttle had her flying as its obviously helping jet the fuel in okay, but of course she died when just in static throttle position. Hope this makes sense. I am trying the fuel filter next as said above. Is there anything I should look out for with this little job in particular? Broken gaskets, O rings etc? Is it just wind off the bottom nut, uncoil the two side clips and let it drop off? Need to get this right. Thanks lads. Made me smile today.

 

[TheHunter990]

Re: Engine bogging down, very little power

Sounds like your carb is the problem since you can pump the accelerator pump and it runs much better (more speed/rpm if understand what your saying).

To me your problem has to be no fuel getting to the main jets. A clog would seem most likely. Take apart carb and inspect. EVERYTHING

 

[Scott Danforth]

Re: Engine bogging down, very little power

Anyway, back to subject. I got a friend to throttle whilst I looked down the carb. I get two lovely jets of fuel for a few pumps,then they sort of die off. I start the engine, (with the flame arrester off...yeah... I know), and see two good jets when it's revved. But after a few more goes, it turns to a spray,then a fine mist and then almost nothing. I took her out around the harbour, trundle was fine (that's for you Volphin!), but opening her up bogged her down again. Pumping the throttle had her flying as its obviously helping jet the fuel in okay, but of course she died when just in static throttle position. Hope this makes sense. I am trying the fuel filter next as said above. Is there anything I should look out for with this little job in particular? Broken gaskets, O rings etc? Is it just wind off the bottom nut, uncoil the two side clips and let it drop off? Need to get this right. Thanks lads. Made me smile today.

we know the accelerator pump is working. However from everything else, It sounds like your running out of fuel in the bowl. This would also prevent fuel from getting to the main jets, however the accelerator pump feeds from the bottom of the bowl, so we can rule out clogged jets since neither are getting fuel.

could be any of these (or a combination)

fuel bowl filled with crud
plugged fuel filter
weak or damaged fuel pump
needle and seat sticking / hanging
stuck anti-siphon valve
collapsed fuel line

 

[Emeraldsnake]

Re: Engine bogging down, very little power

Okay, this is how it went. I first took out the pipe leading down into the tank and checked that the gauze was clean and clear at the end that sits in the fuel tank. It was. The anti-siphon plug was clean and working correctly. The fuel filter was replaced, the old one was a bit squashed but otherwise fine. Replaced it anyway. I removed a spark plug and after removing the fuel line at the carb end, I turned the engine. The fuel gushed out like a tap. So.....I took her out around the harbour. Bogged down as soon as I tried to increase speed. Backing off the throttle picked her up a bit. Pumping the throttle had her moving. Leaving the throttle killed her. So no difference. I get two great jets when revving the engine, so can't be fuel pump accelerator. I had the throttle revved whilst i covered the carb to maybe clear any blockage. Almost sucked my hand in, so that's fine! Well.....the carb is off. Cleaning time. :blue: Got to be a blocked main jet, sticky float or something. Such a shame, she ticks over perfect. A labour of love is turning into a sheer bloody minded challenge not to be defeated!!!!AAAARRRRGGGGGHHHHH!