Merc 3.0 Alpha 1 Dying on the Hole Shot

[PBRman]

Hi Guys,

I briefly searched through the forums but couldn't find anything so I apologize if this is a duplicate.

I had my Merc 3.0 Alpha 1 professionally winterized and just put the boat in the water for the first time this past weekend and then again yesterday. It starts fine (actually better than it ever did!), but when I go to accelerate, for a fast acceleration, it chokes up and sometimes dies altogether. When it doesn't die, it either eventually picks up fine or we pull back and go for a slow acceleration in which there's no issue. After we got on land yesterday, I looked at the outer control arm on the lower speed throttle and it was loose - the lynchpin was in but the arm was maybe 3/8" above the lever (?) on the engine. So I pushed it down but there didn't seem to be anything that would prevent it from rising right back up.

I was hoping I just had to run some fuel through the lines but after two days and 12ish miles it doesn't seem to be. Any ideas?

The painfully slow start really makes for sore legs on a slalom ski, sigh.

Pictures tonight if that will help.

Thank you!

 

[CobiaXL]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

accelerator pump?How long since carb was gone over?Take air cleaner off and look down in carb to make sure your getting nice streams a fuel out of pump.

 

[PBRman]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

accelerator pump?How long since carb was gone over?Take air cleaner off and look down in carb to make sure your getting nice streams a fuel out of pump.

Thank you!

I just bought the boat last August, so no idea about how long it's been since the carb has been checked. So you're suggesting that if nice streams aren't coming out of the pump then the whole pump is probably bad?

Thanks again

 

[CobiaXL]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

Thank you!

I just bought the boat last August, so no idea about how long it's been since the carb has been checked. So you're suggesting that if nice streams aren't coming out of the pump then the whole pump is probably bad?

Thanks again

With engine turned off,pull off air cleaner and disconnect throttle cable at carb,look inside carb and open the throttle..If you see fuel squirting then your accel. pump is working correctly,if not your gonna need a rebuild.

 

[mpdive]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

Accelerator Pump. As suggested, look down the throat of the carb with the engine off . Pump the accelerator and watch for a strong stream of fuel to enter the venturi. A dribble wont do. It should be a consistent stream. The internal acc. pump is a small rubber diaphram in the carb that eventually wears out.

 

[PBRman]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

Accelerator Pump. As suggested, look down the throat of the carb with the engine off . Pump the accelerator and watch for a strong stream of fuel to enter the venturi. A dribble wont do. It should be a consistent stream. The internal acc. pump is a small rubber diaphram in the carb that eventually wears out.

Okay, I've disconnected the throttle arm for the higher speeds and pushed the throttle lever to its maximum extension and then pumped the upper lever, and I've had them both connected and pumped the throttle all the way back and forth a few (10ish) times - Nothing. Not even a drop or enough to smell gasoline. Is ten enough times?

I've attached two pictures: 13 is the my hand on the throttle arm for higher speeds and 15 is the whole engine. You're expecting the fuel to be injected into the middle of the carb via the black fuel line, not the yellow one, correct? Neither appear to be kinked or loose and there doesn't appear (or smell) to be gas leaking.

Should I assume it's the accelerator pump even though there's nothing? How difficult a repair is that? I guess I can search for it, since it's probably been covered many times before.

Thanks!

 

[fat fanny]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

From the looks of your pic you have the butterfly almost closed with that open disconnect the throttle cable and pump the lever itwas connected to and look straight down the the throat(air horn)of the carb that is where you will see or should see 2 streams of fuel out of the venturi cluster if not your most likely looking @ a carb job from what you have described with that mercarb not a bad job kinda like building a model car get the #'s off the carb i.d. plate and order a kit (aftermarketmarine.com) carries a universal kit for all mercarbs for around 40.00 bucks and then by a can of carb soak and read the directions in the kit or in the merc service manual.

 

[mpdive]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

Make sure you do this after you run the engine for a moment. It is normal for a small amount of leakdown after sitting for a while. Start the engine for a moment then shut it off. Then test the accelerator pump. It should have a strong stream of fuel down the venturi.

 

[Don S]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

It is normal for a small amount of leakdown after sitting for a while

No, leakage is NOT normal.

There should be fuel for the accelerator pump even if it sets for a week.

If the accelerator pump is set properly, the idle mixture adjustment has a lot to do with hesitation.

 

[mpdive]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

Actually Don that's not true. Idle mixture is for just that ....idle circuit. The accelerator pump is active for anything over closed throttle but is not tied into the idle circuit at all. At idle the idle circuit is active but anything over closed throttle is part of the main metering system. Hence the pump is part of the main metering circuit. As far as leakdown, it is fairly common on an engine that has sat. When the needle and seat have wear it will drop float level slightly. Is it correct? No, but the only reason I mentioned it is for testing procedures to assure full fuel delivery to test the Accelerator pump. With carbureted and mechanical fuel pump systems, this slight drop in bowl level is immediately corrected on cranking. Thanks again for your response on my water pump question!
Best regards
Mike

 

[Doernuth]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

This may be stupid but here goes... You mentioned having the boat winterized professionally. Did you have it dewinterized? If it was fogged your plugs could be fouled and that could cause the issues you mentioned....

Maybe a tune up will fix the problem.

 

[CobiaXL]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

I dont pay people to work on my stuff but from my understanding I believe dewinterize means add gas and hit start button then charge you 125 bucks for disposal fees....

 

[dubs283]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

I believe dewinterize means add gas and hit start button then charge you 125 bucks for disposal fees

a summerize is free

its included in the cost of the winterize

 

[CobiaXL]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

a summerize is free

its included in the cost of the winterize

That makes sense but Still don't get the disposal fee...Like they don't keep the anti-freeze (If they used any at all)and reuse.

 

[PBRman]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

Actually Don that's not true. Idle mixture is for just that ....idle circuit. The accelerator pump is active for anything over closed throttle but is not tied into the idle circuit at all. At idle the idle circuit is active but anything over closed throttle is part of the main metering system. Hence the pump is part of the main metering circuit. As far as leakdown, it is fairly common on an engine that has sat. When the needle and seat have wear it will drop float level slightly. Is it correct? No, but the only reason I mentioned it is for testing procedures to assure full fuel delivery to test the Accelerator pump. With carbureted and mechanical fuel pump systems, this slight drop in bowl level is immediately corrected on cranking. Thanks again for your response on my water pump question!
Best regards
Mike

The engine only sat for a day, though - I'm not sure if that's long enough?
After pumping the throttle fully connected a few more times, I did finally get the smell of gas, but I couldn't see it. Pumping just the upper throttle lever with the arm disconnected does nothing. I'm going to try it again tonight.

So if the accelerator pump is the issue, is it SAFE to drive the boat this weekend before I get around to redoing the carb?

Thank you all for your help!

 

[PBRman]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

This may be stupid but here goes... You mentioned having the boat winterized professionally. Did you have it dewinterized? If it was fogged your plugs could be fouled and that could cause the issues you mentioned....

Maybe a tune up will fix the problem.

Hmmm, wouldn't that be nice!

I didn't do anything to summerize it except charge the battery, clean, vacuum and kill some spiders. When I had it winterized I asked him what I should do and he said it should be all set. It started first try - better than it ever has. The boat runs okay at idle (coughs occasionally but runs) and runs completely okay at full speed. It's not clear to me why the spark plugs wouldn't be working properly, since the issue is only the acceleration of a hole shot. If this were the issue, would running it a little bit more defog the spark plugs?

Thanks!

Ps. Around here we have really nice free ramps. Everything else is not even close to free; I think the guy who winterized would laugh me right out of the area. I'm going to call him at lunch and see if he has any comments.

 

[PBRman]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

The engine only sat for a day, though - I'm not sure if that's long enough?
After pumping the throttle fully connected a few more times, I did finally get the smell of gas, but I couldn't see it. Pumping just the upper throttle lever with the arm disconnected does nothing. I'm going to try it again tonight.

Is the accelerator pump something that sitting for a winter could unseat/ruin? What about driving on bumpy/rutted roads? The road to the lake is in pretty awful condition!

Thanks again!

 

[mpdive]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

The engine only sat for a day, though - I'm not sure if that's long enough?
After pumping the throttle fully connected a few more times, I did finally get the smell of gas, but I couldn't see it. Pumping just the upper throttle lever with the arm disconnected does nothing. I'm going to try it again tonight.

So if the accelerator pump is the issue, is it SAFE to drive the boat this weekend before I get around to redoing the carb?

Thank you all for your help!

Yea, you should be fine as long as you dont expect to be doing hole shots with it. Gradual acceleration probably wont be a problem. However when it fails completely it will probably stall quite a bit on take off. If you can remember the old days of driving around carbureted cars with deteriorating accel. pumps it's the same deal, Lag on acceleration. A quick carb rebuild will cure it all. If your mechanically inclined, it's a fun and rewarding job!

 

[mpdive]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

Is the accelerator pump something that sitting for a winter could unseat/ruin? What about driving on bumpy/rutted roads? The road to the lake is in pretty awful condition!

Thanks again!

No. It's just the normal wear and tear of a rubber diaphram moving up and down in a metal bore.

 

[PBRman]

Re: Merc 3.0 Alpha 1 Dying on the Hole Shot

Yea, you should be fine as long as you dont expect to be doing hole shots with it. Gradual acceleration probably wont be a problem. However when it fails completely it will probably stall quite a bit on take off. If you can remember the old days of driving around carbureted cars with deteriorating accel. pumps it's the same deal, Lag on acceleration. A quick carb rebuild will cure it all. If your mechanically inclined, it's a fun and rewarding job!

Great!

Can't say I remember that; I'm only 24 so I don't remember driving anything older than a '96 Ford Taurus. I did take apart and successfully reassemble both carbs on my dad's 115hp Johnson outboard; don't remember an acc. pump though... I'm pretty mechanically inclined and have the tools to do the work, but I'm not very good at identifying the problems - hopefully this will help with that!

Thanks again~