Carby clean

[Jarrad stevenson]

Hi all,

Yammy 130hp saltwater series 2 has been a bugger to start, runs perfect after that and super easy to start after the initial start-up. Seem to have the diagnosis down to a small blockage in the carby based off people with the exact same issue with same motor.

Question - do I grab a kit with the new gasket, o-rings and float needle etc and tackle it myself or easier to just book it in to the local dealer?

Haven’t done it before but reasonably handy, have serviced my outboards myself plenty of times in the past. Looked at YouTube and nothing overly difficult so thought I’d have a crack but on other hand guessed mechanic might only charge out say 4hrs max for the job so for what might be a $400 saving do you even bother? Would appreciate some advice off those that have done it in case there’s some finicky little things that means easier to just pay someone.

[Fed]

Operator error or choke plates not adjusted to seal.

[charlsie]

hi jarrad, I've been doing a bit of reading on yamahas lately and they seem prone to trouble with the carbies. the 1st thing to do if you're going to work on them is make sure you have the right JIS screwdriver (japanese industrial standard) they look very similar to posidrive or phillip head screws but are slightly different, in that if you use the wrong screwdriver on a JIS screw, they will "cam out". if you've ever worked on older jap bikes, you'll know what i mean. Alot of people reckon the screws are made of butter and strip easily. it's just the driver they are using. other advice is to run the fuel out of the carbies and don't leave the motor tilted to far back when being left to sit. i would love to hear of anyone else that has had a 100hp yamaha made around 2009

[Noelm]

Don't drain carbs after use, unless storing for a long period, first things first, does your motor have a butterfly choke, or the primer setup? Two very different systems that require very different starting technique and/or repairs.

[Jarrad stevenson]

Butterfly choke, but given the brass screws probably worth just paying someone to do it as don’t need a stripped screw to deal with. Enough headaches already.

Question was all about whether to do the job myself or not rather than diagnosis as Have tried 100 different combinations of starting over past 4 years whether choke on/off and idle lever up/down/partway - and other than bad terminal connections making an annoyance even worse no method has remedied the issue. Also been in to the boat mechanic, checked for water in the fuel etc. only thing that hasn’t been tried is the carby’s and have had someone with exact same issue that was a fouled carby issue so I’m assuming diagnosis is ok.

Thanks for the advice

[Noelm]

OK, an old butterfly choke, first verify choke is actually working, starting procedure should be, pump primer bulb until firm, lift warm up lever way up, push key in, to activate choke (unless it has a seperate switch for the choke) then turn key to start while still holding the key in, once it starts move warm up lever down. Cleaning the carbs is quite easy, but, it has to be done properly, you can't spray them clean, or wash them clean, they need to be fully dismantled and every tiny hole and jet needs to be cleaned out.

[catshark]

was watching a HH rebuild vid and while he was attempting to start the yammie , he started to lift the fast idle lever , but but wait for it he started pumping the fast idle lever up and down about 5 times, surely ive never seen that before ,

[Noelm]

The carby on an outboard does not benefit from "pumping" the warm up lever, there is no accelerator pump like on an old car carb, it may kind of work by getting the lever in the right spot while it's moving?

[Noelm]

The very first job here is to remove the air box, and make sure the choke is fully operational, no guessing or thinking, a full test.

[catshark]

like you say the warm up lever has to right up or when you feel resistance or else it doesnt do anything

[gazza2006au]

Best way to go is get a mechanic to install a fuel primer and you'll forever be grateful on a old 2 stroke engine

Fuel primers are common on old technology 2 stroke engines, think back to old lawn mowers where u have to push the little fuel bulb 3 times this shoots fuel down the carby throat and starts the engine almost instantly (electric start engines) it just taps into your fuel line and the handle/pump siphons fuel and squirts in into the engine

The old closing the carburetor butterflys to self vaccum prime the fuel is a pain in the ass on old outboards

All that cranking no fuel no lubrication... on pre mix and especially if u have ran the engine dry the last time used, not good

[Fed]

Butterfly chokes are just fine so long as they are adjusted properly, a very easy thing to check.
The lawnmower rubber button is a primer bulb to pump fuel into the carby Gazza not for enriching the fuel air mix.

[Noelm]

I don't know of any after market primers that inject fuel into the engine (especially via the fuel line, because that's impossible) but, there is electric fuel pumps that eliminate the primer bulb in the fuel line, they do work, but (in my opinion) pumping the bulb a couple of times at the start of the day is way less trouble than buying, installing and maintaining another pump. A properly operating butterfly choke setup should work well, old carby two strokes are not exactly known for their "turn key" starting, like a modern EFI/DI engine, the later models with the prime start (that does indeed inject fuel into the engine) start way better.

[gazza2006au]

Yeah Fed he is trying to start the engine, not adjust his mixture screws

All the butterfly does is closes off the throat of the carby so the vacuum inside the crankcase sucks fuel through a carby port which it shoots fuel down the carby throat

The same as the fuel primer...

If u have ever seen a fuel primer the butterfly valve is removed and the fuel primer attaches to one of the butterfly shaft hole

[Fed]

I'll leave you with it Gazza. Good luck.