Outboard problems

[JimC]

I have a recurring problem with my outboard which this time I hope I have fixed. The problem is clogged idle jets. Having paid $400 to have the 3 carbies cleaned the problem was fixed. There was gunk in one of the idle jets. However a few months later the problem returned. In between I had drained and washed the fuel tank, checked the fuel line for deterioration and fitted an extra fuel filter in the line. The fuel filter on the motor was spotless as was the inline filter. I cleaned the jets and the problem was gone. However it has returned again. This time I cleaned the jets again, both filters clean. I also dismantled the fuel pump which the tech had not done the first time. The pump had a lot of solidified white crystals in it. I have cleaned this and hopefully the problem will disappear. My research shows that this crystal forms when using Ethanol fuel which I do not do. Is this diagnosis correct, because if it is then my servo might be selling E10 as unleaded. I hope not.

Edited March 31, 2020 by JimC
spelling

[kingie chaser]

Sounds like you need to go to a different servo & different outboard mechanic Jim!

I know some servo's in Sydney were getting pulled up by inspectors for incorrect pumps where people were getting less fuel for the $$.

Could be a tanker putting the wrong fuel into a holding tank as well?

Good luck with it but yeh, Id be going to a different servo for a start!

Edited March 31, 2020 by kingie chaser

[noelm]

Never heard of anything forming from using fuel with Ethanol, best plan is to use a small remote tank with known good fuel as a test, just to isolate a tank issue.

[Smobaby]

The only way the jets in the carburettor can become blocked is by dirt fuel. Most fuel filters used in carbureted outboards is only good for tadpoles and house bricks. Do you have a proper paper type filter before the engine. Obviously the complete fuel system needs cleaned thoroughly even a stray eyelash can cause severe problems. Sometimes ultraviolet cleaning is required as all fuel has dyes which when fuel evaporates will be left in fuel bowels. Once new fuel is introduced into the system partials can block jet orifices causing problems. It doesn’t hurt to drain carburettor bowels periodically to prevent this happening and change and clean filters more often preventive maintenance is the key.

[rickmarlin62]

I had probs with crap in my carbies on 60hp yammie  got sick of cleanin carbies  installed water seperator  no more probs  put 90hp yam on  never had any more probs

[dunc333]

for help by keyboard please state outboard model .hp. 4 stroke .2stroke etc and you will get better answers for your issue cheers dunc333

[zmk1962]

Catching up.  Just another consideration. I had never ending problems with my Aux 4ST 15HP Mariner carbie - float/ float chamber / jets needed constant cleaning. The fuel ran of the same filter that serviced my EFI main motor - which is way more sensitive to clean fuel then the carbie motor - so fuel supply or fuel filter was not the issue in my case.

I started to run the carbie motor dry by disconnecting the fuel line during the last phase of wash down and have not had any problems since. This is a good 4+yrs now. The problem for me was the stale fuel left in the carbie and low pressure fuel pump evaporating and leaving behind gunk which would then block the carbie. Just a thought.

Cheers Zoran

[Fab1]

3 hours ago, zmk1962 said:

Catching up.  Just another consideration. I had never ending problems with my Aux 4ST 15HP Mariner carbie - float/ float chamber / jets needed constant cleaning. The fuel ran of the same filter that serviced my EFI main motor - which is way more sensitive to clean fuel then the carbie motor - so fuel supply or fuel filter was not the issue in my case.

I started to run the carbie motor dry by disconnecting the fuel line during the last phase of wash down and have not had any problems since. This is a good 4+yrs now. The problem for me was the stale fuel left in the carbie and low pressure fuel pump evaporating and leaving behind gunk which would then block the carbie. Just a thought.

Cheers Zoran

Key to carbie outboards Is running them often and keeping the fuel fresh to prevent issues.

     I run mine fortnightly wether it is used or not throwing the fuel in the car and replenishing monthly regardless too.

  Draining carbs and mucking about like that is not needed if you do this unless of course you have crappy fuel filters,fuel hoses,tank,get water in the fuel or simply want to long term store and forget.

   I wonder how often boaties maintain their auxillaries let alone run and flush them often? I'm guessing very few except guys like yourself mate.

Edited April 8, 2020 by Fab1

[Rebel]

I use 98 only, plus a fuel cleaner. I use Nulon Extreme.Five years ago my 4 stroke lawn mower had the coughs. I couldn't be bothered servicing the carby, so I added this gear. The mower went like brand new. I still add it to the mower till this day. I started using it in the family cars. Changed the fuel filter in a Rav4 at one hundred thousand K'S, shouldn't have bothered.

Cheers.

[Smobaby]

Playing with fire once the filter is clogged with debris nothing will help. Sounds like your lucky. That’s why there a replacement item.

[back cruncher]

Hi all...I’ve experienced ethanol fuel that caused carbs on my quad bike to corrode,more like an electrolysis .crusty white corrosion around the brass fittings that go into the alloy carb.

[Rebel]

Hi Smobaby.

The filter wasn't blocked. It was like brand new. These modern day additives work.

[Rebel]

Hi, back cruncher,

Don't use ethanol fuel. Any top mechanic will tell you, NO.

[Rebel]

A friend of mine has a colarado. 3000,000 Ks it had a knock in the motor. Changed the oil added an Additive. The ute is still going 2 years on. No knock.

Cheers.

[zmk1962]

On 3/31/2020 at 11:46 AM, JimC said:

then my servo might be selling E10 as unleaded. I hope not.

@JimC, There is a fairly easy method to test if the fuel you purchased has ethanol:

I have moved the bulk of the original post here to its own topic so that it's easier to reference:

Having said that, I still think from what you described you may have 2 issues going on.

1. the fuel you are being sold unaware may be ethanol mix - explains the white grainy stuff. Use the above test to check what the servo is giving you, or what is in your tank now.

2. if the boat is unused for a long time, the fuel in the carbies is drying out, leaving a gunky organic resin that is also blocking the carbie passages. Disconnect the fuel line and run the motor until it stalls (ie run carbies dry). Or as @Fab1 does ... start her regularly especially in hot weather.

Cheers Zoran

 

Edited April 9, 2020 by zmk1962
simplicity

[back cruncher]

Hi all...rebel,I used the e10 fuel by accident.

[sydney south]

I always us 95 or greater. Motor always runs better and better starting.

During the colder months when the boat is not used so much, I do not leave a large amount of fuel in the tank.

Start the motor every month and run for 1/2 an hour.

So far, touch wood i have never ever had a problem. But not saying that I will ever have an issue, as I may have a dose of bad fuel.

I work on the principles of good duel batteries, good servicing and maintenance and hopefully I reduce the risk of operating machinery in an hostile environment.

[antonywardle]

Etec - 91 unleaded is the prefered fuel. If you use anything higher, you mostly just waste your money

and blacken the back of the engine with soot.

 

[kingfishbig]

14 minutes ago, antonywardle said:

Etec - 91 unleaded is the prefered fuel. If you use anything higher, you mostly just waste your money

and blacken the back of the engine with soot.

 

Yes that's right. The reason is that outboards are low compression. Only high compression engines will get any benefits from high octane fuel.

I haven't had any carby problems since I  made a practise of disconnecting the fuel line when flushing and let the motor run out of fuel. You can't do this with an oil injected motor. Other alternatives are to run the motor regularly with fresh fuel or use a fuel preserver.

 

Edited April 30, 2020 by kingfishbig

[kingie chaser]

9 minutes ago, kingfishbig said:

I haven't had any carby problems since I  made a practise of disconnecting the fuel line when flushing and let the motor run out of fuel. You can't do this with an oil injected motor.

 

When I bought my 25hp Seapro that's how I was shown how to shut my motor down by the dealer.

[JimC]

Ongoing saga. Having check the fuel delivery from the tank to the engine all is ok. Fitted a new diaphragm kit in the fuel pump and motor still runs out of fuel because the pump is not working. I have tried all over the net to get information on this motor but nothing. It is a 2011 30 hp 3 cylinder 2 stroke yamaha. Cant find anything. The pump has 2 diaphragms and 2 flapper valves which are a flat strip which is slightly bent to close off fuel ways. cant see a problem anywhere but no fuel coming through with engine running on fuel in carbys. Not sure how the pump runs but I think vacuum off the motor. Wished I could find a manual!

[Fishop]

On 4/8/2020 at 12:25 PM, zmk1962 said:

Catching up.  Just another consideration. I had never ending problems with my Aux 4ST 15HP Mariner carbie - float/ float chamber / jets needed constant cleaning. The fuel ran of the same filter that serviced my EFI main motor - which is way more sensitive to clean fuel then the carbie motor - so fuel supply or fuel filter was not the issue in my case.

I started to run the carbie motor dry by disconnecting the fuel line during the last phase of wash down and have not had any problems since. This is a good 4+yrs now. The problem for me was the stale fuel left in the carbie and low pressure fuel pump evaporating and leaving behind gunk which would then block the carbie. Just a thought.

Cheers Zoran

I too do this with my little 8hp 2 stroke.  When I flush the motor i just disconnect the fuel line.  Gives it about 5 minutes of run time/flush time before it runs out of fuel.

[wrxhoon1]

1 hour ago, JimC said:

Ongoing saga. Having check the fuel delivery from the tank to the engine all is ok. Fitted a new diaphragm kit in the fuel pump and motor still runs out of fuel because the pump is not working. I have tried all over the net to get information on this motor but nothing. It is a 2011 30 hp 3 cylinder 2 stroke yamaha. Cant find anything. The pump has 2 diaphragms and 2 flapper valves which are a flat strip which is slightly bent to close off fuel ways. cant see a problem anywhere but no fuel coming through with engine running on fuel in carbys. Not sure how the pump runs but I think vacuum off the motor. Wished I could find a manual!

https://www.emanualonline.com/Marines/Outboard-Engines/Yamaha/30HP-Models/30-hp-3-cyl.-(496cc)-2_stroke/Yamaha-Outboard-1996-30-hp-3-cyl.-(496cc)-2_stroke-pdf-Service%252FShop-Repair-Manual-Instant-Download.html

It's a bit older but should be the same . I wouldn't bother replacing diaphragms , replace the pump.

[antonywardle]

Sorry to hear about your issues. I've spent a bit of time this week trying to get a smaller 15HP yamaha running and eventually had a bit of success. I used youtube a lot, and the  two people I used were , ThatBoatGuy and Dangar Marine

Dangar did a video on fuel pumps, and he suggested that if the water cooling pipes were clogged, that it can cause heat and fuel locks making the engine run bad.  They also had a couple of suggestions for testing the pump too

Mine exhibited similar issues to yours. It would run, then stop, run then stop. I pulled the carb off a final time and pulled out the jets and the needle thing on the end f the float. It has some blackmarks on it so after a spray with carb cleaner, and then a spray with compressed air,they all came out much better off. There are no settings with my jets, you just put them back in. This is one jet that I didn't know about, and that was underneath a black cap. The only ting that had aa setting was the idle screw. To set this, I gently screwed it all the way in until it it hit the end, counting how many half turns (for me it was nearly 3) and then took it out and gave it carb cleaner treament.

I spent a week on it in the evenings after work and was rewarded with a reasonably well running engine.

Good luck YMMV

 

 

Edited May 4, 2020 by antonywardle

[JimC]

Finally I have victory. The two metal flapper valves had lost their tension so were not closing. So after I retentioned them so they held closed at normal away she went. The manual says to replace the pump every 3 years but as there is only the two diaphragms and the two valves I fail to see why. Maybe it is because the valves lose their tension. Thanks all for help with suggestions.