Yamaha 4 Stroke outboard difficult cold starting, how to fix.

[@richardpelzer4049]

Thanks for the info, i just ordered 2 after market carbs from amazon one manual choke, one electric, incase the carb fails out on the water, keep them in my tool kit. I hate my 15 yama 4 stroke lol

[@carolb9422]

Your thoughts about flattened gaskets was very helpful. I had a throttle lag that I couldn't understand on my T25LA. So based on what you said about flattened gaskets I replaced the bowl gasket and the gasket on the other side of the carb body 65W-14126-10-00 figuring there could be leakage between chambers. Voila. Everything is now good. Thank-you.

[@TheAndresundqvist]

Many thanks! My F80 had cold start problems before i watched this video. My o-rings was ok but I had dirt inside the fuel orifices. I cleaned it up and now it starts like a dream.

[@jlt7438]

Very thorough and easy to uderstand. I wish your shop was near Nevada.

[@lastminuteprepping143]

Great video!! I have an 02 T50 high thrust I bought last summer, cold starts we’re bad during duck season last fall. I also have a bad stumble when I start to give it throttle. When I first bought it, it idled great but wouldn’t rev above 2000 rpm. I pulled the carbs and the main jet on the top carb was sitting in the bowl and they were varnished inside bad. I cleaned the carbs, changed the plugs and have perfect compression. I haven’t done the o-rings or seals on it, but I’m definitely doing them now. I’m located in Niagara Ontario, so I may just order them from you. Thanks again for the video. I’ve been searching for this info for months now.

[@CanadaWideMarine]

Awesome, glad the video helped. Thanks for taking the time to let me know. If you need any further help you can always reach out here, or email: [e-mail].

[@Micah6and8]

Thank you! Excellent knowledge.

[@davidpham2764]

Thank you so much, learn so much

[@tbayfinn1]

Thanks for the video! I have a cold start problem with my 25 HP Yamaha that I thought was this valve but now will check the seals. I believe the passages for the air and fuel are part of the carburetor body on that size and I had read somewhere that the fuel passage can also become very corroded and difficult to clean out and was going to look into that as well. The engine starts ok when you cover the intake with your hand until it has warmed up a bit. Another issue that probably isn't related is that many times after idling while trolling it won't open up again and seems like it is running on one cylinder and then seems to clear mysteriously for no apparent reason.

[@ahmedemaraa1978]

Thanks for the info 😊

[@raystomberski4480]

Great videos thanks

[@rickzoerman3322]

Thanks for the explanation on that. Good vid!!

[@CanadaWideMarine]

Glad it was helpful!

[@superdoublekapowzler2383]

PRO TIP: When watching this guy, hold SHIFT and press > and you will speed the video up 25% for each press of > and you can double the speed of how he talks to normal.

[@conk8636]

Thank you sir.. Helpful content.

[@CanadaWideMarine]

You are most welcome. Thank you for watching.

[@chrislengyel3763]

Thank you, this fixed my cold start problem. The valve gasket is propritary, but I was able to measure the other o rings. The o ring between the carb and the mounting plate is an Oil-Resistant Buna-N O-Ring, 2.4 mm Wide, 33.3 mm ID you need 4 of those. The 8 o rings in the isolater plate appeared to be Oil-Resistant Buna-N O-Ring, 1/16 Fractional Width, Dash Number 028, but they were a few thou too thin. The new Yamaha ring was .0704 and the one I ordered was 0.065. It was still fatter than the squished o ring and seals great. I would probably try to find a 1.8mm or 2mm o ring in the proper diameter. One interesting side affect was my idle dropped by 100-150 rpms and I needed to rebalance my carbs due to eliminating all those airleaks. ,Don't forget to set the balance and new idle speed.

[@CanadaWideMarine]

That is some great information, thanks for sharing. I am sure it will help someone here.

[@Anthony-du3he]

This is gonna be me. I believe someone was messing around with my outboard 2 stroke setting idle and air mixture by misdiagnosing the root problem(what the video suggested)

[@walkertonheights]

Good video, very clear. Thanks. I would like to know how many amps are drawn. First when it is cold. Then once it is fully out. Thanks

[@TSNOutdoors]

I cleaned a rebuilt everything and replaced all of rings and gaskets put everything back in spec and mine still takes forever to start even on a summer day. It’s a Yamaha F50TLRA 2002. 120psi compression all spark plugs are sparking well. The starter on cranks one second at a time and drops back down and it takes about 20 times for it to fire and then it runs fine. Any tips?

[@deonsmit819]

thx friend

[@CanadaWideMarine]

Thank you too

[@iliaortho]

Can those manifold o-rings be replaced with non outboard, hardware store o-rings? If size is matching. Thanks

[@StanBradbury-mi6mm]

I have a problem with my 20 year old Yamaha It hesitates as it accelerates, can you please help. I’ve cleaned the carbs, engine runs smoothly and revs ok. Thanks

[@larsradantful]

Thank you very much for this great explanation of how carburettors works. I have a Yamaha 2002 F60TLRA from new with 1800 engine hours, it is a trailer boat used in freshwater for walleye and lake trout trolling. The engine is hard to start when cold or first time that day, it normally stalls a least 10 times before it runs fine . I suspect it is caused by a vacuum leak in the prime start system, (as you describe in the video) i also idles a little bit rough around 700 to 900 rpm. i plan to rebuild the carburettors with 4 new carb kits. When the engine was new i had a lot more power (same boat not much added weight) i know that it is quite common that engines lose some power with time, but i am wondering if it is possible to gain some power back? Spark plugs are dry and more on white colour (all 4 plugs similar colour), indicating lean mixture. I am wondering if new larger main jets would yield more power in the mid range 3500 to 4500 rpm?. . Thank you very much in advance. Any thoughts or suggestions will be greatly appreciated.

[@CanadaWideMarine]

In my experience these engines are generally good for about 2500 hrs, although I have seen many with more hours, there is usually some sort of major failure by 2500, (I'm talking pleasurecraft here, commercial use is very different). If you brought that 1800hr motor to me asking for more power I would advise putting your money toward a new motor. That said, you will probably find a little power by pulling the head and cleaning the carbon of the valves, and a valve grind. Adjust the valve clearance, and new timing belt. Not to mention freshen up carbs and intake seals. You can certainly find some power with jetting changes, but if you have carboned up valves that aren't sealing the best, or valve clearances out of adjustment you are handicapped to begin with. Hope that helps a little. Thanks for watching.

[@larsradantful]

Hi, Thank you for the advice, i do boat work part time and i would definitely give same advice to a customer if a workshop would do the same repair/upgrade on a old engine like mine. Since i have experience in rebuilding engines myself, i don't care about the work hours, only the the spare part cost matter. I have seen some F60 engines with major failure before, most of them had been hydro-locked due to operator error, and some of them was used as sailing club companion boat on small rigid inflatable boats (high revs and many users) my engine has 98% of the engine hours between 900 and 3000 rpm, due to the speed restrictions in my area witch is 7 knots. once in a while I sail on the ocean and larger lakes and there I feel the lack of power. if i wasn't so cheap I'd most likely upgrade to 115 Hp Mercury Pro Xs, primarily due to the higher alternator charge capacity at low rpm compared to Yamaha (lots of electronics on board) My engine has no corrosion at all, the timing belt is one year old and the valves are adjusted, compression are within specifications. i tried to de-carbonize the engine this weekend (EGR cleaner and soaking cylinders/piston tops in it) ran the engine with oil system cleaner before i changed oil and oil-filter. It actually helped a lot, it ran smoother and had more power than before. Now i will order 4 pieces of this spare part kit: 69W-W0093-10, to fix cold start issues. To do the valve job i guess i need this spare part kit: 69W-W00010-100 but it´s currently unavailable here in Europe. Do you know what size the main jets are for this engine, and what size or part number maybe be a better choice? Kind Regards Lars

[@Anthony-du3he]

I really appreciate you making this video. I was at a lose at my poor starting. Whats confusing is i am getting a sneezing condition too(2 stroke by the way, 05 70hp yami) it seems to be smoking like its rich. I am wondering if a reset is needed after gasket replacements. On my model there is a red switch. I have read if this fails it could be dumping fuel into carbs I believe🤔 any insight on that?

[@CanadaWideMarine]

Hi Anthony, Unfortunately I cannot give you any insights on your two stroke troubles. We stopped working on 2 strokes about 7 years ago and I am totally unfamiliar with them now. I'm sorry I can't help you but I wouldn't want to steer you in the wrong direction.

[@ErikNemo]

The plunger moves on mine but it's 20 ohms resistance, does it need to be replaced?

[@wish2fish37]

Thanks for this explanation.Any idea on a 9.9hp four stroke Yamaha that starts and Idles fine then when put in gear stalls?

[@CanadaWideMarine]

Lots of ideas. It seems I need to do a video on this as I have had several questions about stalling when going into gear. Until then, here's some info: Generally speaking, the engine stalls when it is put into gear because is is not making enough HP at idle to take the load of the propeller in the water. Keep that thought in mind. Always start with the basics. Put new spark plugs in it, spark plugs are inexpensive and the average non mechanic cannot really tell if a spark plug is good or not, so it's easiest to just put new plugs in it. Check your compression while the plugs are out, if you have a weak cylinder or two it will not be making the hp required at idle. Change your engine oil. I have diagnosed far too many running issues because of old engine oil, (that's a topic for another video, but trust me, fresh clean oil helps make hp and makes the engine run better). Put fresh fuel in the tank, open the drain on the carb and pump the primer bulb until that fresh new fuel drains out the carb. Now, assuming everything else is in good working order we can start looking at causes. Things to check: Idle speed, is it simply idling too slow. turn up the idle speed a little and see if that helps. Idle mixture, generally an engine is more likely to stall when put into gear from a lean mixture, not enough fuel, so richen the idle up a little, half a turn out, (counterclockwise) is a good starting point. If those to adjustments don't fix it we need to start looking deeper. Time to remove the carb and check the seals between the carb and manifold, there is usually a heat shield plastic insulator between the carb and manifold, make sure seals on either side are good and that the plastic plate isn't cracked. Next you will be opening your carb up cleaning the idle jet, it is so small that it takes very little varnish buildup to restrict it enough to cause problems. Watch my video on diagnosis and repair of four stroke carbs: kzbin.info/www/bejne/rV7Oe3iJZat2f6c Hope that helps, Thanks for watching, and don't forget to subscribe so you don't miss a future video on this exact subject.

[@wish2fish37]

@@CanadaWideMarine thanks…that is a big help.

[@EasyRider941]

Check valve clerance most people don't look at it. Yamaha is very sensitive for this.

[@arturoflores556]

Hello, would you be so kind as to provide me with the measurements of the O-rings, not only those of the carburetor, but of the entire intake system, it would really be of great help to me.

[@CanadaWideMarine]

Hi Arturo, thanks for watching. Unfortunately Yamaha does not publish the sizes of the o rings, and it is pretty much impossible for me to measure them accurately enough to ensure they perform as required. If you give me a make model and serial number I will happily provide the correct part numbers.

[@alessandromaggio1101]

La valvola ,si smonta? Ho visto una molla

[@datsritefoo]

..should those valves have constant 12v when key is turned on?? Thanks, and great video

[@CanadaWideMarine]

Yes they do

[@nickromaniuk7012]

Great video, Is there a definitive explanation as to why my F15 Yamaha starts on first pull and stalls after 2-3 seconds for about 3 times, and then runs fine the rest of the day? This only happens in cold weather.

[@CanadaWideMarine]

Yes, there absolutely is a definitive explanation. I just can't know what that explanation is without doing a proper diagnostic on it. It is most likely stalling from a mixture that is too lean, not enough fuel, or too much air. So we need to look for reasons it may not be getting enough fuel, or air leaks into the engine. This is not the only possibility, but a very common one.

[@nickromaniuk7012]

@@CanadaWideMarine ok thank you!

[@user-gi5dk7hy3w]

Have a 2004 50 hp 4 stroke Yamaha that runs very poorly at idle a d when you try to increase rpm it stumbles and stalls. I've removed and throughly cleaned verified all orfices are clear and opened. Rebuilt carbs with all new gaskets and o rings.I've drained all fuel and verified tank is dry and clean of all debris. Fuel pump is brand new. Installed new spark plugs. When i pull wire off plug while running I have good spark.Again the engine starts but very rough idle stumbles then stalls then trying to increase rpm. To get engine above idle I can give a shot of starting fluid and maintaine higher rpm but again not smooth rpm with an occasional miss. I have 120 plus psi on all cylinders. Any help is appreciated

[@CanadaWideMarine]

about the best advice I can give you at this point is to take it to a reputable marine mechanic to have it properly diagnosed. It is easy to replace a bunch of parts hoping to solve the problem, but generally cheaper in the long run to invest in the correct diagnosis and only replace the parts that are needed.

[@nedukas2005]

Hello,I have a problem cold starting Yamaha Four Stroke 115 hp.Can be same problem?

[@CanadaWideMarine]

It could be, but it could also be any number of other problems s well. If you are unsure I always recommend a proper diagnosis from a reputable marine mechanic.

[@incognito-be7is]

good morning. I have a problem with the Yamaha f80, it starts hard when cold, can you give me the part number of the o-rings that I need to replace? serial number is f80aet 67g 1003750

[@CanadaWideMarine]

If you are referring to the intake manifold o rings they are most likely 67f-14239-00-00 and 93210-40m10-00. But best to confirm that with your Yamaha dealer when you order the parts.

[@incognito-be7is]

@@CanadaWideMarine thank you

[@toddytwotones2905]

Part numbers for O rings?

[@CanadaWideMarine]

Hi Toddy, If you would like to send us your Make and model and Serial Number and which O rings you are after, we will happily give you accurate part numbers and price and availability. You can email us direct at [e-mail]

[@buschrpm]

Dumb question... how does it work if my 20hp yamaha does not have electric start or battery? I have a hard time to get it started (about 20 pulls). once is warm it runs like heaven. thanks

[@CanadaWideMarine]

Not a dumb question at all. The cold start valve has a little electric heater in it. even though your pull start motor does not have a battery, it does have a generator to generate electricity to power your ignition system and your cold start valve, once the engine is running. It is important to note that the cold start valve requires the electricity to close, meaning that it does not need electricity to richen the mixture up for cold starting. So, if you are having a difficult cold start as it sounds like you are, you need to look at why. I explain many of the causes in the video. If you are still unsure what is causing the difficult cold start I highly recommend booking a diagnostic with a marine mechanic before you start spending money on parts without knowing for sure exactly what needs to be replaced. Parts are very expensive, a diagnostic for a difficult cold start should only take an hour, maybe 2 with consultation time. A good mechanic will be more than happy to diagnose it and tell you what parts need replacing.

[@buschrpm]

@@CanadaWideMarine thank you! I took it apart... hooked it to an external battery and it works the way is supposed to... The only way the motor starts first pull, is moving the throttle lever up and down about 8 times... it starts, it runs for about 20 seconds no matter what I do... it dies, throttle again this time 3 times... it starts... then one or two more times the same. it warms up and it works like a charm... is a bit annoying and it takes a full minute or so. thanks once again... if you have any tips for me I will take them.

[@CanadaWideMarine]

@@buschrpm By the sounds of it you are experiencing a lean condition on cold start. Moving the throttle operates the accelerator pump which adds fuel to the mixture. So you are either not getting enough fuel at cold start or you are getting too much air on a cold start. check for vacuum leaks, in particular between the carb and intake manifold. If the carb seals with o rings to the manifold replace the o rings if they are old or at all suspicious. the other thing to check is that the fuel supply to the cold start valve is not blocked. this will take a little detective work to identify the passageways the fuel takes from the float bowl to the valve, but you need to ensure they are not blocked. hope that helps.

[@richardpelzer4049]

Also,, the little red duck bill vent in the gas tank cap, swelled up and would not vent, used a small pic to dig that mess out. Guess yamaha uses poor quality rubber products !!