Yamaha 15 hp 4 stroke

[DERF]

Having real problems starting engine.

15 mths old, and have changed plugs and cleaned carb!

Electric start with choke on cowling and at throttle control.. Will not fire when cold until I have tried countless times at various choke settings, from full choke to no choke... does eventually fire and die etc etc .. eventually will fire and run on full choke.. once hot engine fires first turn of key every time.

Any Ideas anyone?

 

[truebrit]

Probably stale fuel, unleaded loses its "ooooomph" after a few months storage, drain your tank and try fresh fuel. Dont waste what you drain out, mix it bit by bit with your car or lawn mower petrol.

 

[tcm]

look, let me have a go...

look, turn key and THRUMMMMMMMM see! Easy! AND it was cold then too!

Chuck away the old petrol, and put new stuff in, cleaned the fuel line and checked the fuel feed. Hot starting and fine running and esp starting/dying often points up a fuel prob. Turning a few times and failing means have a look at the spark plugs - if not wet with fuel means starvation which would be like wot you had. If wet, flooded, so then try no choke and full throttle on startup.

 

[tcm]

Re: old fuel useage.

how boring. Find some snow on an incline, pour bit of petrol underneath it and and explain to the kids how v dangerously inflammable the snow can be, and proceed to ignite it to demonstrate. This normally wins psychological advantage in the snowball fight.

 

[DERF]

Done all that... New fuel etc et....just seems unhappy to start...

TCM, I've turned key and still no Thrummmmpp!

I asked the Yamaha guys at the LIBS.. who were decidely unhelpful as I wasn't looking to buy one of their new shinny ones.....one bloke actually said "we don't deal with second hand motors"!

I'll re-do everything again and try..... if it doesn't work I'll have to take it in to Yamaha....

I'm sure its a simple fix... like pull out choke 3/4.... turn once.... put in choke turn once..... open choke 1/4 and 3/4 throttle... then as TCM puts it.....
Thrummmmmp.......

 

[domlee]

Try a good squirt of something like 'EasyStart' into the air intake when engine is cold, if the engine fires easily and even runs for a few seconds then this would indicate a fuel/carburation problem, if it is still difficult to start (when engine cold AND using Easy Start) then the probability will be an electrical/ignition fault. If stripping a carb down, I soak the parts in brake fluid which seems to get them really clean - you'll not believe how a grain of dirt/dust can cause problems.. Try a colder plug.

 

[Roy]

Did you leave fuel lying in the line and carb? This causes most of problems I have found. Get old fuel out and dry out the gubbins. Then refill with fresh fuel, that is fresh from the petrol forecourt, not a stored tin or whatever. Also take out plug/plugs and clean with wire brush. Spray some quickstart stuff down the cylinder before putting plug back in. After all that, if no go, then nip it down to local cheapo mechanic who will start her up for a few quid - usually!

 

[DERF]

Thanx Domlee , Roy..

Have done all of the above but not tried easy start.... that will not cure the problem and I don't want to HAVE to use Easy start each time.

Fuel is new at the worst 2 months old.

I'll strip and clean carb again and try a colder plug and see if that cures it.

Thanx again.

 

[rickp]

I got the impression that the Easystart was a diagnostic step. Work out if its ignition or something else (rather than a long term solution). Perhaps I am mistaken.

Rick

 

[Wiggo]

Derf, FWIR unleaded starts to gour 'sour' in as little as 2 weeks, though I suspect this all total crap. Ours started first time after 3 months when I used it last, although I had to pull start it as the battery was dead.

A colder plug won't make starting any easier - that's all to do with how fast it dissipates heat once the lump is running and up to temp.

Clean the carb with carb cleaner or whatever, use fresh fuel and make sure that when you push the key in, the choke really does actuate. Likewise the knob on the engine - check with the cover off that it actually does do something when you turn/push/pull it.

I know it sounds dumb, but I've spent a happy hour before now trying to restart an outboard with the choke inoperative becasue the lever had fallen off at the carb end...

 

[DERF]

Erm... just re read Domlee's post again slowly...... you're right.. my apologies Domlee, Roy.

 

[DERF]

Thanx for the tip Wiggo...

Wasn't quite sure about the tech side of a colder /hotter plug so I've learned something. Was willing to try tho.

Never thought abut the choke no actuating!

 

[Col]

I assume you prime the carb each time?

If you disconnect the tank every time you finish using engine, you will need to squeeze the priming bulb a few times to fill carb up.
Before leaving engine for any length of time, switch off the fuel, disconnect the tank, and let the engine run out of fuel to stop it. This means next time you use it you are squeezing fresh fuel into carb. Even if fuel is the same mix as the last time you used engine, you will not have evaporated so much of the volatiles off as if you had left it (fuel) in a (hot) carb.

 

[JKay]

Howzitt /forums/images/graemlins/cool.gif
biltong in the choke circuit ,Clean everything and change the fuel filter even if it looks clean pour some Klippies thro the engine and off you go

let the engine run with the fuel disconnected when you leave the boat for any length of time

Cheers China /forums/images/graemlins/grin.gif

 

[DERF]

Bokke

Geeze, the first Bokke to reply to a post..

Welcome to the forum man! Loads to learn and a great bunch of guys on here.

is that Klippies with coke or neat?

Where's your boat based?

 

[JKay]

Re: Bokke

Lets see how the cricket goes tomorrow before we decide if we,re bokke or poms like Strauss did! /forums/images/graemlins/ooo.gif

Klippies with coke about fifty fifty in a pint mug should do the trick /forums/images/graemlins/shocked.gif

boat's based in the Brayford pool in the middle of Lincoln about 50 miles from the wash and about the same from the Humber /forums/images/graemlins/grin.gif

Tot siens swar

 

[domlee]

Quote "A colder plug won't make starting any easier - that's all to do with how fast it dissipates heat once the lump is running and up to temp."

I beg to differ... in certain conditions a colder/hotter plug may make starting easier - it all depends on the current state of the plug! I suggest DERF looks at the following site and compare the images to the spark plug in his engine.

http://www.gnttype.org/techarea/engine/plugs.html

I always think of spark plugs in much the same way a coroner examines the goo in a heavy-smoker's arteries - they are usually a sure indication of the probable cause of death...