f115 won't start

[yockman]

Hi guys,<br />any diagnosis much appreciated:<br /><br />Yammie F115, 2001.<br /><br />ran well all day yesterday, till back in port. Siwtched it off while waiting at the boatramp, then hard to start, wouldn't idle at normal speed, needed heaps of revs from the throttle, died every time I put it in gear. Blowing black smoke. Eventually got it on trailer<br /><br />Back home, started first go on the muffs and ran perfect.<br /><br />Went to start it again on the muffs this morning, no go. Tried and tried, it only gave the occasional cough. Pulled out plugs, all very wet and very petrolly.<br /><br />Any suggestions?<br /><br />Cheers and thanks in advance<br />Yockman

 

[rodbolt]

Re: f115 won't start

hello<br />most the time this is a stuck needle in the vapor seperator. black smoke means a severe flooding problem. not bad on a 2 stroke but can cause excessive wear in a 4 stroke. its possible an injector is stuck. but not likely. its difficult to see but behind the airbox runners is a gray tube leading from the top of the vapor seperator to the front inside edge of the airbox. remove the tube and pump the fuel primer, if gas squirts out the needle valve in the VST is stuck. requires intake manifold remocal to access. a test for a stuck injector will require the use of a fuel pressure gauge on the fuel rail test fitting.

 

[bossee]

Re: f115 won't start

Try to run it on a small outboard external gastank and see if it start then (to eliminate any fuel delivery problems). <br />- Do You have a built in internal gas tank in the boat?<br />- Check all fuel lines from tank to outboard including the bulb and filter.<br />- Do You have water-fuel separator on the fuel line?<br />- Is the battery and connections in good shape?<br />- Do You have the outboard serviced regularly by a Yamaha dealer or do You make the service Yourself?<br /><br />I have a Yamaha F115 2003 myself.

 

[yockman]

Re: f115 won't start

Thanks guys,<br />Bo, it's got an underfloor tank, but the problem's still there with the external tank. There's a near new racor filter on it, near new battery and yamaha guy does the service.<br /><br />Rodbolt, I'll check the vst. I'm not the most mechanically capable, but prolly not the most mechanically challenged either. assuming the vst is the problem, how do you unstick it and is it a complex job?<br /><br />Cheers and thanks in advance,<br />Yockman

 

[rodbolt]

Re: f115 won't start

first remove the vst vent line. if its the vst needle you will see gas spurt out when you pump the primer. the vent is the gray rubber line from the topof the vst to the airbox. if that is ok then remove the vacum line from the pressure regulator on the fuel rail and cycle the keyswitch. if no fuel spurts from it it is ok,no ruptures. if those two are ok it leaves a stuck set of injectors ir a groundede wire in the harness. a fuel pressure test gauge can find them. however my bet is in the vst. if all 4 plugs are wet it sounds like its flooding. they only way toflood all 4 cyl is by something common. to access the VST requires intake manifold removal. not hard just another gasket.<br /> I would also test for spark. however use a spark tester. you want to control where the sparks are. with a known fuel problem you may have a lot of vapor blowing out the plug holes. no need to blow the vapor past a plug cap that is arcing . if you dont see fuel spurting from anything obvious its time to test the subsystems to eliminate them. compression,spark and fuel. but I have seen the needle seat lock come off a few vapor seperators and cause flooding. usually will drip gas out the air box as well.

 

[yockman]

Re: f115 won't start

Thanks again rodbolt.<br />Re all 4 plugs being wet, they were more than wet, actually soaked with excess petrol pooled in between the thread and porcelain! <br />The boat is some distance away and I'll have a go at it next weekend. Very keen to get out cause there are some jumbo yellowfin about at the moment.<br />Back to the stuck needle - what causes it to stick and what do I do to stop it sticking again?<br />Cheers,<br />Yockman

 

[rodbolt]

Re: f115 won't start

hello<br /> just as a needle seat in a carb, a tiny particle of trash can do it. also I have seen the lock tab that locks the seat to the top of the vst come loose. at a minimum you will need an intake manifold gasket if you remove the VST. may take a VST seal ring with you as well.<br /> but do the tests before dissasembly.

 

[yockman]

Re: f115 won't start

I sure will do the tests first. All that info is much appreciated, rodbolt. <br />I'll let you know next week how it went.<br />Cheers,<br />Yockman

 

[yockman]

Re: f115 won't start

Bought a stack of parts including a torque wrench, headed off down the coast for the weekend, connected the muffs, turned the key - vroom vroom. Did 14 hours on the boat over the weekend and it ran perfectly <br />Glad I didn't have to take off the vst, it looked tricky<br />Happy ending.<br />Thanks for the advice anyway.