Just repowered w 2003 Mercury 50hp, won't run

ERock82

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Just hooked up my new outboard and it won't fire up

I recently bought a 2003 Mercury 50hp 2 stroke outboard and just finished hooking it up last night. I bought a new fuel line plug connector and put 5 fresh gallons in the tank. I cannot get the motor to fire up. It is turning over but not firing. There's no gas getting into the cylinders. Here is a list of what I have done/check:

1.) There is spark on all 3 cylinders
2.) The fuel bulb gets hard and I can hear the fuel moving through the fuel pump
3.) I tried squeezing all fuel lines going up to the carb. I am fairly certain that I can feel pressure in them going all the way to the carb.
4.) I tested 2 batteries (The boat battery was reading 12-12.5 volts and sounded strong) (The trolling battery read a solid 12.5 volts and sounded strong as well) I went home and put a charger to the rolling marine battery and it was at 70%.
5.) Motor was definitely in neutral when starting. I checked prop also on this. Killswitch is working fine.
6.) I cleaned spark plugs and they stay clean, so no fuel getting into cylinders



NOW, here is what I know about the motor:

1.) I bought it last weekend and it fired up real nice several times in a row
2.) It is very clean and appears well maintained
3.) Compression was 120 on all 3 cylinders
4.) The man I bought it from used a forklift to lower it into my vehicle. I drove it 2 hrs without any problems and had a buddy help me lift it out of the vehicle. It was heavy but we did not once drop or set it down too hard. We lifted it several times going a few feet each time before lifting on the transom.
5.) My old motor was a 95 Force 2 stroke. The plugs are the same for both motors and it seems they are a perfect connection
6.) Gas was fresh. I pumped an ounce or so in a cup and quality looks good.
7.) The man I bought it from drained all gas and fluids before loading it



Here are my thoughts:

1.) Maybe the battery needs a 100% charge. It sounded real strong and had spark when I cranked it so it makes me think that probably isn't it. I'll try anyway.

2.) Maybe from lifting it out of the car onto transom, the float pin got stuck??? Now, there are 3 carbs?.so what are the chances all 3 got stuck or does just the top one need to be stuck??

3.) It took me a lot of switching and adjusting to get the throttle cables right. Could I have messed something up with the throttle that is not opening the carbs?? I don't recall messing anything up. I just kept taking the cables on and off and moving throttle back and forth a lot.

4.) Could there be an air leak in the fuel lines? I actually saw gas come nicely out of the line before I attached the new Attwood connector which plugs in good. Also, even with an air leak, wouldn't there still be fuel getting into the carbs if I kept pumping the bulb?

5.) I am using the permanent fuel tank for the boat. Used to have a portable one. I cleaned this one real good and inspected for leaks (for gas?not air) and I saw gas smoothly pump out. Could there be an air leak in either the gas tank line or on the pump bulb line? Because the bulb gets hard I would think it could start for a little bit. The bulb does soften after a few minutes though when just sitting.

6.) Water in tank? I tried squeezing bulb for a minute to see if anything was in there. The gas that came out when I lured it didn't appear to have water in it. Also, tank was sealed pretty well and fuel gauge at zero initially.

7.) Water in carbs? Could the seller have had water still in motor that drained into carbs when transporting??

8.) Connection from Force to Mercury not 100% correct??? It turns over nicely and has spark...



Here are things I don't think could be the case but who knows...

1.) Bad fuel pump. Why? Because just a few days ago the motor fired up real good again and again. The fuel pump looks very clean. It wouldn't just fail and from lifting the motor out of car, I can't see it getting messed up.

2.) Gummed carbs: I don't think so because the man said they were cleaned not long ago. Also, it ran great a few days ago. It would be too odd for that to be the case now.

3.) Air Box: How could that be damaged all a sudden? That seems doubtful


Please, if anyone has an idea what this could be or how I can narrow the problem down please let me know. I will call the seller in a couple days if no luck. I have a 90 day warranty but don't want to drive 2 hrs if I can fix this easily.

I am thinking maybe it is something really simple due to the fact I just hooked this motor up and switched from Force.

Thanks in advance!
 

yzf125

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Are you using the Enricher/Choke to start ? Or does it even work with your harness ? Try pulling the airbox cover off and using a gas/oil mixture in a spray bottle mist each carb as you try to start.
 

ERock82

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Are you using the Enricher/Choke to start ? Or does it even work with your harness ? Try pulling the airbox cover off and using a gas/oil mixture in a spray bottle mist each carb as you try to start.

I tried a few times using the choke. I tried with holding in the ignition and then went and manually pressed the black button down on the choke itself. Is the air box cover easy to remove and put back? I don't want to get into a mess and void the warranty. I assume it is blocking access to the carbs. I don't want to move the oil reservoir though for sure.

Can I rule any of my items out from my "thoughts" list?

The plugs are both 8 pin. The seller felt confident they would match. It was a 1995 Force 40hp originally.
 

ERock82

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Also, I want to note that there was a solid thin black and light blue wire on the Mercury side that is left unplugged. These are not the tilt and trim wires. Those are (green w/ white stripe) and (light blue w/ white stripe).

On my Boat side 8 pin plug there are 4 wires that just hang. Two are for the trim. The other two are a light tannish pink and grey/brown w/ white stripe. I followed them up to the dash and they were never being used.

Those 4 wires on my boat side plug were never used when I had the Force.
 

yzf125

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The airbox "cover" only has about six small screws holding it on and is easily removed to expose the carbs.
 

ERock82

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The airbox "cover" only has about six small screws holding it on and is easily removed to expose the carbs.

Okay, thanks. I will remove the cover.

Tell me if my thinking is correct here:

My research tells me that if fuel IS getting into the carbs and there is NO FUEL getting into ANY of the cylinders, then it is usually a stuck float pin or gummed carbs.

NOW….what are the chances that ALL 3 float pins got stuck??? Wouldn't it fire up on at least 1 cylinder if one of the three carbs was good???

I would think this could rule out the carbs being stuck and make me lean more towards fuel not getting to the carb.
 

yzf125

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You could very easily open a fuel bowl drain plug on the bottom of any carb and see if fuel comes out. ( Choose easiest accessible one ) This will eliminate your thoughts on the needle being stuck closed. The best way to get this to fire is the method I recommended.
 

ERock82

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You could very easily open a fuel bowl drain plug on the bottom of any carb and see if fuel comes out. ( Choose easiest accessible one ) This will eliminate your thoughts on the needle being stuck closed. The best way to get this to fire is the method I recommended.

Okay, I will try this: Now, just a few questions:

1.) Could my electrical connections and the fact that I just repowered have anything to do with this issue? What is the likelihood?

2.) Could my control cable installation have anything to do with this?

3.) Could it still be the battery?

4.) Could it be the tank not properly venting?

5.) Could it be old oil that go clogged into fuel filter?
 

yzf125

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Could be a hundred different things but you need to focus on one thing right now... 1: Start with seeing if fuel is getting to the carbs, most important because that was your initial complaint. Then test as I suggested in my first post.
 

ERock82

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Could be a hundred different things but you need to focus on one thing right now... 1: Start with seeing if fuel is getting to the carbs, most important because that was your initial complaint. Then test as I suggested in my first post.

Ok I will do that. Can I just spray some starting fluid into the air box instead?
 

yzf125

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I wouldnt use starting fluid as it has no lubricating properties for the motor and just spraying into the air box does not directly hit the carb opening either, You have to remove the air box cover. Take a spray bottle with some premix fuel and spray each carb directly.
 

ERock82

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This is actually an update to an update:

Update to this problem:

I tried some new things and still no luck

1.) I sprayed more gas into carbs and pumped bulb?..still died out. I think that might eliminate a bad fuel pump

2.) No matter how hard or long I pump bulb, I can't get any fuel to come out of carbs from bowl

3.) When I spray carbs with fuel to start and run for a few secs, I can't see any fuel coming from the jets at all

4.) All carb bowls are full

5.) I replaced my tight bended old fuel line with one that fits much better??did absolutely nothing.

6.) I left gas cap open for some attempts?..seems to not make a difference anymore

7.) I tried using another gas tank. Now, it was just a fill tank (not a tank you would use while on the water). I took the primer tube and put it in the nozzle opening and it vented through the same hole. The bulb did get harder easier (guessing the shorter distance to motor?) but this did not solve the problem.

Do I need to use a legitimate portable tank with separate vent and fuel line connect to truly test this or would this have been good enough for the test?

Could this be a bad primer bulb? I don't want to go spend $50 on a new one if it ain't broke. How can I know for sure?

Some posters will say stuck float needle or clogged jets BUT?.

1.) Why did it run perfect days ago at the shop?
2.) What are the odds ALL 3 Jets or ALL 3 needles get stuck?? I mean, I can see 1 or 2 and I've had carb issues before on my old motor and it would at least run but really badly.
3.) It does start on it's own without spraying carbs sometimes. Just not for long. A second maybe.

My father swears it's a bad gas tank but I told him I tested with the other.

Are there a few more tests I can do on my tank?

Here is what I know so far:
1.) Cleaned and inspected tank several months ago when I redid the deck. Sealed it up until I hooked up lines a couple months ago. It was empty and I confirmed no water or debris in the gas.

2.) Tank did not leak any water when I cleaned it (I dried it for days outside so you know)

3.) I just replaced the main fuel line and put new clamps on

4.) I inspected and cleaned vent hose (not sure what replacing will do)

5.) Large fill hose doesn't leak fuel (don't know about air)

6.) Put a new sender on it which works great by the way

Possible thoughts:
1.) Could the tank have an air leak (it's plastic) Would that even matter?
2.) Could taking the vent hose completely off (would vent throughout the fitting on tank) be a good test?
 

ERock82

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I've done all the checks and it's definitely a fuel problem. It won't start at all.

Here's what gets me:

I tried opening the gas cap and it started right up for a few tries BUT even with it open it won't start anymore. Only worked a couple times with that.

Very confused

I've tried two gas tanks with no luck and changed my fuel line on the permanent tank. Fuel IS getting to carb bowls (3 carbs)

It's a 2003 Mercury 50hp 2 stroke.

That gas cap thing seems like something KEY here in the problem BUT why won't it start again???

Vent line is good and clear.
 

jbcurt00

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E,
Try not to start multiple topics about the same problem. It's especially helpful to see ALL that's been done so far, even if it still won't start.

I changed the title to this topic and merged it w/ the previous topic.
 

yzf125

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Try starting it with some throttle engaged , To do this you need to press the center button in and hold it on your controls and move throttle forward to disengage the trans. and allow you to rev the motor without the trans.
 

ERock82

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Try starting it with some throttle engaged , To do this you need to press the center button in and hold it on your controls and move throttle forward to disengage the trans. and allow you to rev the motor without the trans.

Already tried. Nothing.
 

ERock82

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This motor has the oil pump removed. A plate is in it's place. Now, I've read something online about the oil pump interfering with the fuel pump. Could there be something I don't have connected properly or not at all connected wiring wise that could contribute to this?
 

ERock82

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I'm really going for the obvious here: If I really was sold a good motor and not scammed I think the motor must be fine. It's either:

1.) I did not connect something properly when hooking things up

2.) Something on my boats end such as:
a.) Bad primer bulb/hose
b.) Bad Attwood plug connector (just bought) It fits and clicks though
c.) Bad permanent gas tank
d.) My test with gas can was not good bc it was just a reg gas can not portable tank
 

ERock82

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Update:

I just called the seller. I should have done this 2 days ago.

He said, since he drained all of the fluids out that I need to choke it extra long. His steps:

1.) Pump bulb firm
2.) Hold choke in for up to 20 seconds and start and keep pumping choke?.if no good
3.) Have someone start with key while I manually press choke button on motor?if nothing
4.) Advance the throttle in neutral a little while doing all of the above

I think he might have said to keep pumping bulb while holding manual choke and have someone start at key

Guess I'll try all of these combinations.

Thing is, I don't recall hearing anything from the key choke (no clicking)

Manual should work right?

I have used the choke before and for about 10 secs while pumping and it seemed slightly better but no start. Maybe ignition choke bad.
 

ERock82

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Could carb adjustment cause motor not to start?

I'm running out of ideas to why my outboard won't start. I know it's a fuel problem but I have eliminated several things:

2003 50hp Merc 2 stroke

Here is what I know is not the problem:

1.) Carbs are fine. Nothing stuck
2.) Primer bulb is fine
3.) Killswitch on and working
4.) No clogs on fuel lines or filter
5.) Fuel pump is working
6.) Gas vent not clogged
7.) Plenty of gas in tank and new lines not kinked
8.) Choke is being sufficiently used
9.) Always in neutral
10.) Advanced throttle while choking
11.) Clean gas and oil

Here is what I'm left with:

1.) Bad quick connect (just bought it at Walmart) How would I test?

2.) Carb screw adjusted too lean? I never touched these but I thought I remember the guy I bought motor from adjusting something. Is there more than 1 screw? It ran great when he showed me. Could this possibly be it? Would the motor just not start at all if 1 screw was adjusted improperly? I'm thinking this couldn't be it?.
 
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