running a boats carburetors dry

Johan

Senior Member
When storing a boat's outboard you are suppose to run the carburators dry. In other words you have to disconnect the fuel lines and run the engine until all the fuel is out. Other than preventing oil from building residue inside the carburator what is the purpose of this?
 

buckles

Senior Member
as well to get rhe salt water out of the pipes of the cooling system. Salt water will corrode the water pipes
 

Ajay

Senior Member
As far as I know it is simply to prevent the build-up of petrol residue gums and varnish in the float bowls of the carbs which then could prevent the needles from working smoothly when it is re-filled NB They MUST be re-primed BEFORE towing anywhere after standing empty to prevent damage to the needles.They could also be drained manually (rather than running dry)by unbolting the drain bolt at the bottom of each float bowl--
 

Hammertime

Sealiner
Ajay is 100% correct. However this only need be done if you are going to be standing for long periods.
The best way to keep those outboards in prime shape is to start them twice a week at least. If we stand for two weeks as is the case now, I start the motors every second evening and run them on the muffs. Guess that's why they look and perform the way they do after many hours of torture. One thing with the muffs is don't run them long, and don't put them into gear and open up.

When you are going to tow again, make sure you have primed them and started them in the driveway, boat house etc. I am always amazed at how guys get to the beach/slipway after a lay-off and are pi$$d off cos nothing works.

That could bring us to a whole new topic - wheel bearings, steering, links etc. hmmm
 

Yeldman

New member
I was told by a outboard motor mechanic to rather not let the carbs run dry on pre-mix 2 strokes as they wil not all run dry at the same time and when the motor cuts, there might still be some fuel left in the carb. The petrol will evaporate and a thickish sludge will be formed by the oil that stayed behind. Rather use the little drain screw on each carb to drain both petrol and oil. I suppose this will not be a problem in oil injection/ autolube models.
 

Johan

Senior Member
Hammertime you are absolutely right. I always make sure that each engine has run for at least five minutes with the muffs BEFORE going to sea. Its just not worth it battling with engine problems on the slipway, never mind stealing valuable launching time from other people.

I start the engines about 2 times a month when not in use. Maybe I should make the service interval a bit shorter!
 

Hammertime

Sealiner
Yeldman - funny enough I was told the same thing from a dude who has been servicing outboards for at least 30 years full time for big name boat shops.

His advice was just run them on the muffs regularly and you will be fine, so thats what I have done for many years and never had a problem.

You got one of the best boats in the world in that Avatar of yours!
 

Ajay

Senior Member
Ja Yeldman that would make a lot of sense in theory.Even the jets are differnt sizes for the differing heights on vertical so float bowls would almost certainly not empty simultaneously . Altough one would hope that they should empty fairly evenly, and if the motor got to the point of cutting out, then after standing, the gum left over time from a small amount of leftover fuel would surely not be the same as an entire floatbowl full evaporating??? I suppose any residue is too much though ITO a non-sticking needle or clean needle-seat.

I run mine minimum of once every 2 weeks but my port motor is only just up and running again from mid Feb with its lower unit done and starting it was a drawn out stressful affair even though I knew it was all OK.Its happy now but 2 stroke outboards definitely dont like standing.
 

cpt chris

Senior Member
hi guys i think the most important thing about running your motors reg ,is that your crank which is lubed by the outboard oil in two strokes, so it is not good for a 2 stroke to stand as the crank gets no lubrication its easy to clean carbs but buy a new crank my 115 yamaha set me back nine grand if a boat has to stand take out spark plugs and put straight outboard oil +- 10mm in each hole swing motor with plugs in without firing to prevent corosion and drain carbs ofcoarse
 

dugongboy

Sealiner
Something I was told some time ago - Never drain when towing - start at least monthly so that old fuel in carb is replaced by new - only drain if the motors cannot be started in 2 months or less and as cpt chris said put extra lube into each cylinder if standing for 2 months or more.

My 25's are 9 years old and from new I have started at least monthly and once a year done a hot carb clean with Quicksilvers carb blaster I change the plugs often and flush after every outing, after priming and choking they start in 2 pulls(from cold) - so far so good (touch wood)
 

mukie@wolfgat

New member
yes i have started the boat.

it starts well with the muffs 

took it on the water.

it revs up and everything

on the sea water it dosnt pull . like there is a lack of power.

drives slowly. no speed.
 

tkei

Sealiner
Have the control cables been replaced recently??? Had a similar problem once when I had replaced cables, and had installed one of the cables incorrectly and as a result only got minimal power.
 

Ski Scout

Member
Hi there

Strip and clean the carbs manuallly , making sure the pilot jet and idel jet is unblocked /clear...use air and thin steel trace wire to clean blocked jets...nothing inflexible and wider than the hole is to be used. 

If the jets are clean then the air / emulsion tubes in the carbs also have to be blown out and reemed with thin wire to remove  gumed up fuel. Inveraible this is were the problem lies....

Thirdly check the plugs caps.....if there is corosioion on the inside ...dump them....you could get a break on the spark transfer...happened to me in paindane......replaced them with NGK plug caps and hey presto...she was running fine again

Its a process of elimenation good luck and trust the above of assitsance

rgds

rob
 

Cracker jack

New member
Guys,

I once had a similar problem with a relatively new outboard motor on my duck. Starting the engine was easy and even revving it up was no problem (in and out of the water), but under load conditions she did not want to rev up. After many expensive services and attempted repairs, I finally discovered that the fuel station where I used to fill up my boat tank, had a leak in its tanks and that the fuel was contaminated with water. I drained my boat tank into some transparent bottles and could clearly see a fair amount of water in the fuel. After flushing my tank and my carbs and refuelling at another fuel station, the engine was perfect again. Interrestingly the water in the fuel did not affect my car at all.

 
 
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