Outboard Starting Problems and How to Fix Them Part 1: Simple Checks and Easy Fixes

A discussion of outboard motor starting problems, some of the causes and quick solutions, aimed at non-mechanics. Includes an overview of the 4, 5 and 6 HP Tohatsu / Mariner / Mercury motor, basic checks if the motor won’t start, why it’s hard to start the outboard after draining the carb, how to check for fuel flow, how to test and correctly gap the spark plug.
www.theca.org.uk/

[@stovic1442]

Been figuring out outboard maintenance by trying to get a 2005 Suzuki going. So many in depth videos and text but not until yours did I grasp some of the crucial basics. Today one flaky old motor is running and I've learnt a few things. Thanks!

[@SumsView]

absolute best and most thorough video I've found on this, great job!!

[@delstep2255]

Simple useful video. No extra personality, straight to the point. Thanks

[@luissasmith2192]

Thank you.

[@solosailorsv8065]

Best video on this I've seen, Well Done ! So I'll contribute: Air leaks in the the fuel lines are often overlooked as problems. On an external tank, squeeze the primer bulb and leave it compressed, and take the connector off the motor. It should HOLD VACUUM. If not, fix that leak. The tiny holes in the carb are almost invisible (near the choke plate, side of Jets, etc) Clean with a copper strand of wire (always use copper to clean holes, it is too soft to scratch. The smaller the motor, the MORE sensitive it is to constricted venturi Ensure good compression and check the valve clearances each season Clean the water outlet hole with a small zip tie or similar (mineral deposits) Ignition "Safety" switch shorts your spark to ground. It should measure OPEN with a meter when ready to run Don't yank the cord, it will wear the plastic gears fast. a steady pull is best and easier on your arm. Cheers !

[@luissasmith2192]

Many thanks for your feedback. Great tips you highlight too - appreciated.

[@rilla64]

You are correct but you mean a vapor leak that would be sucking air in if anything was coming out of the fuel line anything out would be gas Vines are important and yes you get a vacuum leak they need the correct air fuel mixture. And my experience it's usually a fuel related issue. But if it's not you tend to notice that real quick spark compression good gas. I confirm old school Two Strokes. 25 or 40 horsepower 2-stroke had a lot more power I don't mind four strokes I wish they would stay simple and not go computerized I like my motor simple

[@ashatola]

Doh! Pulled on that damn cord about 50 times before I gave up and found this video. First thing was "make sure the lever is turned to onboard or exterior tank. Mine was turned to Off. Fired up on the second pull. Thank you!

[@captainjamesmcbride2344]

Great video Dave, very nice delivery, no rush and you made it very simple to understand. Thanks mate. Nice advert for Laverda on the back of the overalls too! Excellent. Hope you are keeping well mate. Cheers

[@CruisingAssociation]

Glad you enjoyed the video James. We agree, it was great and have passed your kind comments onto David.

[@ia6980]

Best troubleshooting video out there, thank you

[@waynethompson7597]

Thanks great video once I found out where the carby drain hole was refilled it with fuel started first go did all the work throughs you did in video thanks

[@luissasmith2192]

Thank you.

[@thebigbeachclean3075]

Thanks for this I hadn't started my outboard for around 2 months so it must have been dry . Started up first time with the external tank

[@jcfgh]

Excellent. Thank you.

[@grahameire3845]

Excellent video 👍thank you

[@amandaproctor7041]

Top notch video. Thank you for taking the time to make it ☺️

[@luissasmith2192]

Thank you

[@zack9633]

Hi, Thanks for the video, Could you please comment with some Trouble shooting, tips on what to do with a stuck gear shift handle. I have not done anything yet except managed to get the engine running. I know I will need to replace gear oil and impeller. could you list possible causes why the handle gear shift handle is stuck and what to do. the outboard has been sitting doing nothing for the last 4 years on a stand. it is a Johnson 6 HP 4 Stroke model number J6RL4SU (year 2006). Thanks

[@BoydGoldie]

Great video. I learned a lot. Very minor comment is that the video is mirrored so writing is backwards and tightening the sparkplug was anticlockwise. Must have been your setting on the phone/camera.

[@CruisingAssociation]

Thanks Boyd. David, who produced the excellent video, says 'Thanks for the feedback. The mirroring was the result of using the front(selfie) phone camera lens in some shots so creating a mirror image. Sorry if it was confusing - I’ve avoided it in later videos.'

[@eduardocortes-dv4lo]

Maestro, What if the sparks are too big? Ex. I have a Yamaha 4 stroke 9.9 JMH s, i put a par of new sparks gap size 10 , they fit bud took 5 drags to start the motor. should be gap 9? Why the drag is so hard to pull? Thank you

[@luissasmith2192]

Thank you for your question. The standard spark plug for that motor would be NGK CR6HSA, with a 10mm outer thread. Check your engine manual and follow the manufacturer’s specification and you should be fine. There will be equivalent plugs available from other manufacturers if you don’t want to use NGK. Personally, I would never fit a shorter or longer plug than the manufacturer has specified.

[@paulschulz8205]

Have battery juice, trimming up and down, radio and speakers come on. Engine bot starting?

[@meletuitupou508]

How can you tell if the water pump is broken on a small boat engine?

[@erichadden77]

I got a mercury 9.9 2 stroke that wont start. I replaced 2 coil packs and tried 4 sets of plugs. I got one plug sparking and the other one has no spark..replaced wires and still nothing.. switched plugs around and the one that did fire, dont fire after the switch. I know nothing about motors and dont have the money to take it to a shop. Carb gets fuel for sure. I can smell it when I turn it over and it floods. When I first got the motor, it wouldnt start by the key..but after alot of tiring pulls it would start and then run all day. But it just wont do a cold start.. any ideas what could cause it to only get one spark to one plug?

[@CruisingAssociation]

Hello Eric, our KZbin channel isn't intended to be the place for advice beyond the videos we publish (joining the CA www.theca.org.uk/ gives you access to a range of benefits including member only forums with over 6,300 members worldwide contributing), however, we've checked with David Fickling who produced the video and he says: I have no experience with this particular motor, but given that you’ve replaced coils and plugs and still don’t have a spark, then I would suggest checking through all the electrical connections and looking for corroded or loose contacts. Especially check that the HT lead to the spark plug is screwed fully onto the connector inside the plug cap, and that the connection onto the coil at the other end is also firmly in contact. Just because you can smell petrol doesn’t mean that the fuel is getting to the motor in the correct mixture. If the motor has a history of being left unused with fuel in the carburettor then it may well be that the carb jets are blocked, so stripping and cleaning all the jets would be a good move. I also understand that these motors have a primer pump that you have to operate a couple of times to squirt fuel into the carb when starting from cold, so you might want to check if that is working properly.

[@jerzyciechanowski4598]

Great video, why is it mirror image?

[@luissasmith2192]

Thanks for your comment. I used my mobile phone to make the movies and some scenes were taken with the front ‘selfie’ lens, which results in the mirror image effect.

[@jerzyciechanowski4598]

@@luissasmith2192 Thanks, 👍

[@gemale]

It’s great tutorial but didn’t work for me. I have 5hp Coleman . Did carb clean approx 5 times. Plenty of gas flow . Spark is good. Have compression . Still after 34 pulls not start. Tries both internal and external gas tank. Pls advise and help any further tips. Thanks

[@WhiteThunder1296]

Have you figure out your problem?

[@gemale]

Thanks for checking . I just gave up and exchange that motor with Mercury !!!

[@WhiteThunder1296]

@@gemale thanks for fast reply. Ye you made a good choice mercury/tohatsu are reliable engines,wish you to make alot of sea miles with it

[@ia6980]

I have 6hp tohatsu, i was running it dry after using it in ocean and it seemed to overheat and shut down, after which i couldn't restart anymore, i tried cleaning carb, checking filter, replacing spark plug, doesnt work, ive noticed some salt deposits on body of of the motor and some hoses, also throttle was difficult to turn, somehow throttle cable is loosened and very difficult to turn.

[@luissasmith2192]

If ‘running it dry’ means that the engine was run out of the water, without any cooling water supply, then the impellor will probably have been destroyed and the engine may have seized. But if you just refer to running the carb dry of fuel, then please see the video where we discuss the problems with getting fuel through these engines after they’ve ‘run dry’. You need to pump gas through using the squeeze bulb from an external tank until the carb fills, else it’s really hard to start the motor by just pulling the cord.

[@goryglory729]

Hi boss I ran my Yamaha 8hp 4 stroke (external tank only) with the air vent of the gas tank closed and it (because of the vacuum I created) stopped running after quite a while. Now it's extra hard to pull the start cord and even if I pulled it won't start. Do you have any insights how can I make the motor run again? Appreciate your help.

[@luissasmith2192]

I assume that you’ve checked that the motor is not in gear before trying to start. It’s just possible the engine has seized and that’s why it’s hard to turnover on the starter cord, but I can’t think why just running with the vent closed would cause that. If you remove the spark plug, and, with the engine in gear, try turning the propellor by hand you should be able to feel if the motor is turning freely. If it is then it’s not seized and you need to look further for a cause of the starting issue. If it’s seized then unfortunately you need a rebuild.

[@goryglory729]

@@luissasmith2192 Thank you for your response. I removed the spark plug, pulled the cord with much more ease, put the spark plug back in and pulled the cord again. Now it runs like a charm.

[@dancole298]

Thanks…my 20 hp Mercury shut down because of low oil. I added oil and cannot grit it to pull start efi four stroke…. Help

[@luissasmith2192]

Thanks for your enquiry. Sorry Dan I have no experience with efi motors and can't help.

[@arawaiatiira2512]

Hi.ihave a 30hp yamaha the problem is when u take out the top cap and then its runs fast but when close the cap its runs slow with smokes comes out please can help me with it

[@luissasmith2192]

If the motor speeds up when you remove the fuel filler cap then maybe the air vent in the cap is blocked or the vent valve seized shut. If the water pump has failed then you’ll get not water jet from the cooling water outlet - that could also be due to a blockage so the only way to be sure is to strip and check.

[@8180634]

For the priming problem when using the built-in tank, just blow into the tank to create a little pressure, then it will fire right up. The fuel pump won't prime itself if it's full of air, but once it has fuel it pumps fine. This covers it: kzbin.info/www/bejne/pISln4OXjZp7rZo

[@chadkurszewski1967]

I had the same problem, and don't have an external tank to simply use the bulb (if I had an external tank, I'd be using the external tank!). A CPR-like mouth-to-tank breathed life back into the motor!

[@Chris-Bowen]

It will prime fine if the external tank is full. If the fuel level is below the fuel intake on the carb then the pump does not seem to be able to pump fuel up to the carb. If it is not then you can be pulling on the starter all day. I learnt this the hard way. Twice!

[@Rob-fx2dw]

Don't put copper grease n an engine with an Aluminium head. Only use copper for Steel head engines or you will risk getting deterioration of the alloy. For Alloy engines use a suitable alternative or just a drop of oil or grease.

[@jasonbignal7621]

I'm having problems with the starter cord

[@luissasmith2192]

Please explain what the issue is and we may be able to assist.

[@jasonbignal7621]

@@luissasmith2192 when ever i drawn the starter cord I'm hearing a slamming sound or a clip sounds engine starts once or twice but didn't keep up cause didn't get to push in the choke in time

[@jasonbignal7621]

@@luissasmith2192 I've noticed that a spring and a clip that opens up the plastic thing to spin the wheel was missing and so i get another starter head but still having the problem

[@johnnylawrence]

Got a 1992 9.9 evinrude and i triple checked/rebuilt the carb, replaced the power pack, charge coil, ignition coils, spark plugs, primer bulb, fuel pump, water pump, new fresh gas and STILL wont turn over. I have plenty spark from both plugs. And checked the killswitch and that works fine (obviously since i have spark). And whats weird is even when spraying ether in the carb, or spraying inside the spark plug holes, even putting a little gas in there, it STILL wont fire. Sometimes it sounds like it wants to for a second but then dies. Im at a loss here. Anyone who has any ideas much appreciated.

[@luissasmith2192]

That sounds really frustrating. The next things to think about are incorrect mixture, incorrect spark timing, or poor compression. The latter can be tested if you have or can borrow a compression tester. I have no experience with that motor so cannot advise on how to check the timing, but perhaps there’s help out their on the web. For the mixture, obviously the choke must be working to start from cold so I’d check that, and also look for air leaks for example at the inlet manifold or head gasket, which would weaken the mixture.

[@johnnylawrence]

@@luissasmith2192 i checked compression with a tester and get 110psi for both. Near the end of summer i bought a gasket kit. This spring im gonna take the block out and replace all gaskets and i think ill find something wrong once i do that, hopefully :)

[@johnnylawrence]

Update: i took the block out and replaced all gaskets. Put everything back, fresh gas, and it started and ran. But, ran rich and after running for a few minutes i stopped the motor, tried to restart and it wouldnt- for a while. Next day id start it again, it ran but then after a while die out, and wouldnt restart. So today i jreplaced the fuel pump, and still wouldn't start. I dont get it. It ran last week and now it wont. Anyone got any ideas?

[@montemaguire4596]

What if I had gotten my boat back fe the mechanic and did hear it run before I left. Then I didn't try and start it myself until 2 weeks later and it starts up and run at high RPM then I shut if down and it never stats back up again. And I originally had the mechanic replace the throttle cable and I noticed they didn't hook up 2 ling cage system's. What do I do ?? Help

[@luissasmith2192]

If you can return it to the mechanic then that would be the best solution. Otherwise check the cables and linkages and the throttle and choke operation - sounds like something is stuck.