No fuel?

[thinwater]

I have had problems starting both from day one.

I replaced the fuel lines and in-line filters with twin Raycor separators; I had of these one on my prior boat, and it dealt with e-10 separation very well. I also relocated the lines lower and replaced one of the primer bulbs. Now I have good down-hill fuel supply to both engines. So far, so good.

I ran both 2 weeks ago. No trouble port, but the fuel quick connect wouldn't stay on starboard (PO removed it every trip and I think has worn the fitting) so I replace the line part. It then ran fine for 30 minutes at the dock.

Today, port is fine. Went out and ran it for a while under load. Smooth. But starboard won't. Starts fine on starter fluid, any throttle setting. I by-passed the quick connect and could primer bulb pump gas through the fuel pump. I also let the fuel pump go into a can (hose off) for a few moments; not much volume, just little pulses, but I guess that is all that there is.

Suggestions? Stuck carb float or valve? As Anytom pointed out, the carb is against the outside on the Starboard engine and is unpleasant to get to, but looks possible with a manual and patience. Pulling the engine looks like a back injury.


The thing about twin engines is that you have twice the odds that one will get you back home, and twice the odds that you'll be working on one of them. Boy do I miss the Nissan on my last boat; never worked on it in 12 years... but I guess these are 12 years old now.

[Allezcat]

Thinwater,

There are anti-siphon valves in the fuel tank. These require quite a suction to open by overcoming a spring loaded valve. If the engine starts and runs ok using a remote tank you may have a weak fuel pump or a sticking anti-siphon valve. As a cold starting technique I advance the throttle about 3 or 4 times before starting. This sprays fuel into the carb throat.(assuming there is fuel in the bowl)

Chet
Allezcat 36010

[Page 83]

Its good to pull the fuel line off the engines and let them run dry. When fuel is left in the carb bowls it evaporates, leaving a couple drops of water and some shellac in the needle valves. This makes the idle valve particularly difficult to adjust. I promised you that shop manual; I'd better find it and get it out to you!

[Marc Gershel]

The anti-siphon valves caused me grief for a long time, until I realized that they were the problem. I removed them and haven't had a problem since. This was around 10 years ago. I dont know why they are even needed. The fuel lines are higher than the tank.
Marc

[Lady of the Lake]

Marc,
Isn't that exactly why we need the check valves? I thought they were to keep the fuel from draining back into the tank since the fuel lines were higher than the tank. I wanted to take mine out too but left them in for exactly that reason. I suspect mine are not functioning properly either. The only other thing I have changed was added fuel/water separators in line and they might be contributing to the idle issues. I may have them mounted too high. Right now they are the highest point in the system. Lower and they get a lot more salt spray. Anyone have any thoughts?

[amytom]

With primer bulbs at each engine, don't the primer bulbs have check valves in them? Would that keep the fuel from returning to the tank?

[thinwater]

If I take the hose off the engine fitting it will flow. I tested this when bleeding air from the Raycor. I also installed an air vent leg on the Raycor exit; it flows under gravity alone too. I do not know why the anti-syphon valve is not working (PO removed?) but I do know that there is good clean fuel there.

My last engine (Nissan) had no tank ASV and life was good. It was an all-gravity system, all down hill. Always started first try. There was a brass shut-off valve. I never drained the carb bowl and never fogged it (ran it every 2 weeks all year). Perhaps I was lucky.

I doubt water; I sumped the tank and the bowl of the Raycor is bright. I suspect that the fuel pump is the thing - it really was pretty lame, in retrospect.

[Allezcat]

I believe the engine is below the fuel tank. The reason for the anti-siphon valves would be to stop fuel from feeding a fire in the engine compartment should there be a line ruptured.

Chet
Allezcat 36010

[Allezcat]

Thinwater,

Have you tried new spark plugs? I know it sounds elementary but if one plug is fouled it screws up the whole system since both plugs fire at the same time. The only other thing I can think of is a leak somewhere in the fuel line such that the fuel siphons back into the tank and the engine then just sucks air. I guess if you have a hard bulb shortly after you start to pump it that would eliminate that possibility. I have discovered that on my bulbs I have to turn one end above the other to make the bulb pump. If I turn it end for end it does not pump anything. Weird!! These engines should start with just a touch on the starter if everything is working correctly.

Chet
Allezcat 36010

[thinwater]

so that they can clear air through the carb. Pump them downwards and they will not get firm - the air is trapped and creates a cushion.

[Page 83]

There are three sizes of anti-syphon valves; 1/4, 5/16 and 3/8". The springs are strongest in the large sizes, and offer more resistance. I up-sized my fuel lines and created a problem. Going back to 1/4" made some of the problem go away. Pumping the throttle 3 times, and setting the MANUAL CHOKE on the new engines completely solve it. Now I let the engines warm up by gradually opening the choke, and have the idle set for warm conditions.

[Allezcat]

Thinwater,

If you cannot resolve the starting/running problem after all the fuel checks you may have a weak spark caused by a bad CDI or Stator. These two items can cause all kinds of goofy symptoms including hard starting one day followed by no problem the next.

Chet
Allezcat

[thinwater]

a) Removing the starboard carb in the boat was not a big deal after all, and no need to consider pulling the motor: 2 wires, 1 clip, 1 hose, 2 bolts. 10 minutes later I was looking at the inside of the carb, seeing that it was dry, and seeing some junk as well.

b) The needle was stuck, the idle passage was restricted. A rebuild kit and some spray cleaner was all it needed.

c) FYI, the idle screw adjustment was ~ 4.5 turns out, which is a good bit further than some suggested, but it is the same on both engines.

When I was finished I went over to my Stiletto (18hp Nissan 2 stroke) to start the engine, just for maintanance. It has been ~ 2 months. I never use treatment, never drain the carb, not in 15 years. I do run a Raycor fuel filter. Less than 1 second on the starter and she's off. Granted that Yamahas are pretty good if they have been run in the last 48 hours, but why can't they be like that? Just venting.

[Page 83]

Have you reviewed the engine section of the old message board? There are some more checks there. I'll be at HHN saturday, stop by if you see my minivan and borrow my engine-hoisting-thingie, (and Eric's comealong!) if you want to try to hoist the other engine just high enough to rotate and work on it. That way you can leave the controls connects and not risk feeding those little clips to the crabs. Several owners routinely disconnect the fuel line and run the engine dry to prevent glazing and "jelly-fication" in the carb bowl. If you get de$parate, I have a very good Yamaha mech who was still doing house calls last summer. I still have my old engines.

[thinwater]

No, I believe they start and run normally. No ignition problems or intermitant problems. The day after working on them and the day after that they started instantly and warmed up very easily. I then dropped them into gear, and they ran strong, pushing lots of water at full revs without a stumble. Just not like my Nissan. I had a johnson before that, and it was like the Yamahas - very good and ran strong if it had not been sitting too long. If had sat for a while, it just took time to get fuel to the bowl and then it would warm-up and run fine. That's what these seem to like.

I have always wondered why some designs are prone to varnish and some are not. The Nissan is not. My chain saw is not. Does 2-stroke oil reduce the tendancy? I have read some posts to the effect that this is true; instead of forming a tough varnish layer, an oil film is left behind which easily flushes away a the next use. But this seems too simple, too obvious. Would a 150:1 oil mix do the trick?

I have done 2 articles for Practical Sailor on fuel additives. One concerned e-10 and additives that proclaimed to help with water drop-out. None did in standard ASTM tests developed to test this property. The other concerned diesel bio-cides and was also based upon laboratory work. There were some surprises there as well; the additivies behaved differently than might be expected. The pooint is this; there is a lot of urban legand out there regarding additives, storage, and engines, and very little - none - real research. It may be time to try something different.

I guess I will just have to go sailing more often.

I will be in Deale tomarrow (sleeping on the boat) and I will be certain to swing by mid-morning.

Rigging up and engine hoist was easy enough, after reading a few posts - I just did not need it. I did wrap the engine/water gap with a sheet before starting, just in case!