How to check fuel flow on outboard 

A common mistake people make when attempting to prime a fuel line from a previously empty fuel tank is forgetting to hold the primer bulb in a fully upright position while squeezing the bulb. This enables the valves in the primer bulb to function properly. Another often missed step in systems with large fuel tank line filter systems is neglecting to fill the canister with fuel after changing the filter. If you leave the canister empty you will be forced to squeeze the primer bulb many times to fill it before fuel will actually be delivered to,the engine.

1995 60hp Tracker cranked no start (sat idle for a year) this video showed me how to check for gas to carburetor, opened the bowl drain, pumped the gas ball to flush out old gas, started right up. ( already had put fresh fuel and enzyme additive in tank) . Thanks for taking the time to show me how to trouble shoot.

Great video, professional and right to the point. Unlike others on RU-vid that play music in the back ground and waste time wanting to hear themself talk. Keep posting! 👍🏻

I don't do a lot of work on engines, but when I do, I usually get a refresher and I'm always reminded of how intuitive they really are... fuel oxygen spark. Thanks

Great video and narration, very helpful!

Thanks for doing this, the store told me I should be able to just squeeze the pump and fuel would come out, didn’t work. Watched your video and it made it easy to see that you need to push that connector in for fuel to come out. Did that and it confirmed it was working. Saved me an unnecessary 75 purchase of a new one

GREAT video. Easy to understand and informative.

Very well explained. I tend to jump in too fast and miss little essential checks.

Man you are the best. So to the point and clear.

This video is the most helpful video on RU-vid. Thank you so much 🙏

right on....i got about half way through the check...will continue and thank you

Very informative, I will be able to find my problem. Thanks

Nice video! My 8 hp tohatsu wouldn’t idle. Took off the carbs and cleaned out the jets. Put back together and it ran perfect.

Thank you! Very helpful to remove the mystery of an outboard motor!

Good video! Straight the to point and informative. Thanks

Such an informative and easy to understand video! Thanks a lot!

thank you very much for the help turn the fuel mixture down starts up really early now

Wow! Great video. Quick and clear instruction. I needed this last spring.

Great video. Very clear and helped me out. Thanks

Wow thank you. You're vidieo was very informative and I could see everything you were describing. Simple clear and concise

Awesome video! Thank you for sharing this education

Great video. Traced my issue to a dodgy primer bulb on the external tank fuel line.

This just completely opened my eyes thanks a lot man!

Very helpful. Thanks for the video.

Great video, guy's like you make it worth it. Thanks so much.

thanks for the video very helpful

2000 model 40 hp Johnson outboard. New fuel tank ,line and primer bulb. Engine recently gone through (maybe),it runs good,but will Sometimes not run unless you constantly squeeze the primer bulb,other times it'll run fine. Don't want to just start throwing parts at it....found your channel,you seem to be well versed on the operation of outboards. Hoping you or a subscriber can guide me to the proper troubleshooting needed to get the engine running properly. thanks in advance.

Great tips. Having trouble with fuel getting to carb. Very helpful thank you.

Perfect explanation, great video thank you!

I love you man! Fixed!

This is one hell of a video thank you very much. Exactly what I was looking for 👌👍👍👍

Going thru this right now on. A Honda 20 hp brand new but haven't run it in 1.5 years. The gas in it had stabilizer. I got fresh gas and will purge the old fuel thru the bowl hole you indicated. Thanks.

Great video mate!!

Great advise thank you it answers my low power at full throttle, carb was not getting a good flow due to a crushed hose :)

thanks for the tips

very helpful video, thank you.

One of the best explanations of outboard motor fuel flow, excellent job😊

Very good clear advice!

This is proper troubleshooting. Thank you!

Great. Thx. Watching from Ontario Canada

We rented a small fishing boat on a lake in the Sierra Nevada mountains. It would run for a while then quit. We looked around and saw a lot of other boat renters waving for a tow. I found that priming a few squeezes would get it started but this time when it started to stumble I'd give the bulb a few squeezes kept it going. Annoying but better than rowing! Interesting that every boat they rented had the same problem huh?

Very thorough info...thank u!

I see why you have 1.5 M views, calm commonsense advice. Well done, subscribed.

Very helpfull i just got my boat out of the shop and its still not running right and it runs but starts cutting out when you give it full throttle then it dies after a few mins it will start back up idles great till you give it the juice....thanks

great vid really helps thanks

Your boat motor videos are the best on the web. I've learned a ton from you. Thank you!

Great video, do you have on how to adjust the carburetor for low trolling speed at higher altitudes?

Very well explained Thanks

That was a good way to verify that you had fuel to the carburetor using the pressure created by the fuel priming bulb. You did miss out on mentioning the other main culprit of fuel starvation being a faulty fuel pump. I am having an issue with my kicker and I already eliminated my fuel line as a culprit by removing my connection to my main tank and connecting to a known working portable tank. Today I am going to connect a “T” fitting into my fuel line after my pump and check the amount of fuel pressure as well as the consistency of that pressure.

Well explained video. Thank you

Very good video, Thank You.

Great RU-vid instructional video!!

bought a little boat with a 35hp motor, one of the things that i just noticed while unsucesfully trying to start it was the one way pump was installed in reverse and i realized that during this video lol

Good detailed video

Good Video, I think that is why my problem is.

This guy in the video is also a legend in the Avaition community

great video!

Very good video

Good morning great video, I have a Mercury Black Max 150find the started this last weekend would not start I pulled the screws out of the bottom of the carburetor bowl and oil ran out. Upon further investigation I discovered that the oil reservoir cap at the top of the motor was cracked and allowing air to come in I am assuming did this allowed the oil to gravity drain into the carburetor bowls, is this a reasonable assumption?

great ideas! gonna try the all

Very helpful indeed! I just need to change my fuel line from the center console gas tank to the water separator No clue how to get it from the console tank The flow is restricted Presumably trash on pick up

Thanks for making the vid

Beautiful. Thanks. 👍👍

Should the float needle when the bowl is full prevent you from continueing to pump bulb?

I have a mercury motor on my boat 115 Hp it sometime has a good speed and sometime to slow what could be problem?

Great video

I have this exact motor. I've removed and cleaned the carb. I have not fully disassembled the float mount or the spring pin; simply because the inside base of the carb bowl was almost immaculate. Do you have a jet cleaning tut as well as a carb float set tut? Because I think that may be my issue. Im not a mechanic at all so I dont take something apart unless ive seen it a number of times.

Guess what I'm doing tommarow morning! Thank's, for this video, makes sense and cheaper than replacing parts etc.

great vid.

Awesome, Thanks a bunch.

great video

I have a 1997 Mercury XR6 150hp 2-stroke EFI (recently purchased). can you show fuel system from tank fuel flow? ie, is there a backflow valve inside tank. Does the fuel pickup nozzle in tank have a filter?

Also check the condition of those o-rings at each end of fuel hose

Good video thanks

Thank you so much!

1980 mercury 50 hp runs fine in neutral and low rpms but when I open the throttle up it won't go into that higher gear...runs like a 10 horse! I changed plugs, Sea Foamed the carbs, but no real results. Saw your video and remembered the bulb doesn't really get "hard"...🤔...sound like fuel filter? If filter in tank is clogged then it wouldn't pull enough fuel to let the bulb get hard would it? But if the engine filter was plugged, it would get hard! What do you think? Thx

Do you recommend an inline filter?

I have a mercury 15 2012 model runs excellent cold or warm when you have stopped it and left it for about 10 to 20 minutes it Cranks for a while before starting again but then runs well would really appreciate your help wondering if it might be an air leak

Thank you

Hello, nice video... I have the identical outboard, but I have the opposite problem. I disconnect the fuel line when I transport my boat and reconnect when I get on the lake. The last few times, when I reconnect the fuel line, prime and try to start the engine cold, the motor floods. I remove the spark plugs to dry them off, and leave them out a while to dry out the cylinders, then it starts. Any suggestions for how to prevent this flooding?

Thanks for the video. I have a 25 Mercury 2 stroke. Cranks every time. Idles great. Runs full throttle great. Problem is often it bogs down when throttled. I have to nurse it from idle and finally it will run after letting the throttle off several times, then it will go to full throttle.

Don't pump the bulb to hard or you can stick shut the needle valve on the floats. Also make sure the vent on the fuel tank or cap is big enough for proper fuel flow to the engine at wide open throttle. If it isn't the engine will bog down until you back down on the throttle.

I have Honda 50hp, was running good. I added more fuel to tank, now it’s mkt starting.

This video saved me hours...

Thanks my brother

I have a 2001 Johnson 2 stroke 50 horse power outboard motor. It starts right up cold/or hot. However after I ride for an hour and then stop (to swim or restaurant), it will not restart. Sometimes it will takes 2 hours to restart. And when it restarts, it starts quick. Vaporlock? driving me crazy. Mechanics can't fix it because it starts right up for them. Help please.

I figured it out the top carb wasant getting any fuel.The float was stuck shut. Thanks

Enjoying watching your videos, very informative! What would be your opinion on an Evinrude 140cc outboard 2-cycle pre-mix oil(ounces) per gallon of gas. Can't seem to find an info on this. Thanks for all your help!

Did u do a carburetor cleaning video

I have rebuilt my carbs on a 40hp mercury it idels great but when you go to excellerate the motor just bogs right down I have a brand new primer bulb and line plenty of fuel out of the fuel pump. what else can i look at ? thank you for your help

I have a mariner 6 hp outboard and just got an external fuel tank for it. Should the fuel line be on or off while running it because when it's on it fills up the internal tank and when it's off it doesn't start.

What about overfueling? I have a 98 Johnson 115 that does not idle well then does better at 1/4 to 1/2 throttle but bogs down again at full throttle for several seconds before finally smoothing out and getting up on plane. The engine runs fantastic on plane at WOT as well as lesser throttle but once you slow back to no wake speeds it begins to choke out and eventually dies out. Once this occurs it will not start unless you disconnect the fuel and turn the motor over several times. I can make it work but it is a bit of a pain. Any suggestions?

With the new cheap after market bulbs they put a plastic liner to keep the ethanol from eating the rubber . The liner has been breaking lose and blocking the fuel . you can pump it and see some fuel come out but its not flowing when its connected one brand that a lot of people are complaining about is the attwood . This is causing a lot of carburetor rebuilds for nothing . Show how to test to make sure the flow of the gas is coming from the bulb .Get a Attwood bulb cut long ways for a side view of whats going on inside and how the plastic liner is stopping the fuel from flowing like it should . I went through 3 attwood bulbs in one month and was having engine trouble do to lack of gas getting to the carb . I finitely went and got the 30.00 mercury bulb and now it runs perfectly . I wish you would make a video showing this new way the cheap bulbs are being made are not allowing fuel flow . Look at the reviews on the attwood bulbs . This problem is going to cause a lot of headaches . I'm just glad I figured it out without rebuilding my carb .

I got a 2014 Yamaha 50hp four stroke, and it works normally fine until i pull the box so i can get more speed. When i pull it, it wont accelerate as good, and it wont raise in speed. Any tips?

Yes very helpful

What if ball pump doesn't get hard? Thanks for the great video.

Informative video... Now my problem consists of the fuel system not holding pressure. I pump the bulb it will start and run... Sometimes stalling I reach back the bulb is soft again and requires pumping... I re-pump and it will start but runs like it's not getting enough fuel.. I know this cause I proceed to pump bulb while engine is running and then it begans to idle better and run correctly... I cut it off and after having fished for a while... anywhere from 30 minutes or longer, I go to start it and again no pressure and have to start all over again with pumping before starting and then pumping it while it's running... Long I know but you seem astute in this area

I have a 1994 yamaha 40 hours. Starts great and runs at times. However, some of the time I'll go to start boat and warning sound goes off and stays on. When this happens boat runs good at low speed/rpm, but seems to bog down or misfire at higher speed/rpm. Is this the fuel pump or fuel lines needing cleaning?

So I have a 25 efi merc and my motor after running rough totally died. I can prime with the primer bulb and get fuel to the engine fuel filter but there's an inline clear glass filter before the vapor seprator the is clearly not filled with fuel. I tried priming with the hand bulb filling it up and hitting the electric start but either way its still empty. Could my fuel pump have went out? I had drained all fuel from the whole fuel system including fuel rail cause i thougt i had water in my fuel.

Great info, im getting plenty of fuel to the carb so next ima check the jets,i have a tahatsu 4 stroke 8hp looks just like that, any other suggestions if it's not the jets?