2005 50 TLRD stalls out in gear

[margaritaville]

OK, quick run down
Engine has been a nightmare for 2 years. Head, cylinders and all 3 carbs were replaced in July.

Went through the break-in period and put another 20 or so hours on it.

Put Sta-bil in the gas last time out and had about 2 gallons left over when I got done.
Boat sat for 3 weeks.

Now when the engine goes in gear and you gently bring up the throttle it stalls. However, if I pin the throttle, it runs fine.

I changed the fuel filter, used a new tank of gas and changed the plugs, but no luck.

I am thinking that the low speed jets are clogged.

Can I remove the pilot screw and use carb cleaner in each carb?

[boats.net]

You are better off removing and cleaning carbs.

[dorf]

I was wondering if you solved your problem with the new carbs.

As I researched mine/your problems I discovered that (if I remember correctly) one carb has a different part number than the other two.

Your problem still sounds like carb adjustment- boat-fuel line problem.

It is hard to imagine that 3 new carbs have not corrected your problem.

If there is trash in your carbs a 10 micron fuel filter is a suggestion.

Have you tried to adjust the carburetors? Mine has a screw on one side of each of the carbs that you can adjust them with.

As mentioned, if you want to clean the carburetors you may as well take them off and take them apart and clean them that way. If you have an air compressor or a can of compressed air, shoot through all the passages (esp the needle) and make sure they're clear. While you're at it it's always a good idea to let them soak in carb cleaner.

[margaritaville]

I ran it today and did not adjust anything. What I dsicovered is that with the engine all the way down, the engine will stale, consistently.

With it trimmed up above level, it will run much better. I am thinking a stuck float.

All 3 carbs were brand new back in July, installed and synched by the yamaha techs.

The engine has a yamaha 10 micron filter installed and it has been replaced every time the engine is accused of having a gas problem. It is BS. I have 3 boats with 3 different engines, buy my fuel from the same location and only this engine has a problem.

Something tells me it is a bad design, but of course yamaha will not admit to it.

[dorf]

Let us know what fixes your problem, when it happens.

I was going to buy a Johnson E-tec but it was not avail where I bought the boat.
Folks say that the Yamahas are "bullet proof" and most probably are.

I cut my 10 micron open to see what was inside, not much. There is allot of surface are in there. You can cut it open with a 32 tpi hack saw around the circumfrence at the top, where it screws to the mating flange.

Cheers !

You say that the engine runs fine pined I assume this means W.O.T. Is this in netural or under load?? When you pump the primer bulb before starting does it get nice and hard or does it seem to keep taking multiple squeezes?? You say it idles OK so that takes low speed charge coils out. Is it sneezing in this in between throttle operation? Your list of problems may be as long as the boat in feet. At which point (RPM) does it die?? Whats the point at which the engine dies?? Anything above idle? More input can dial me into a solution

the two stroke 50 is not the best motor yam put out

Neither is the 40...

[margaritaville]

wayner,
What problems have you experienced or heard about the 50? Obviously, Yamaha will admit to nothing

[margaritaville]

You say that the engine runs fine pined I assume this means W.O.T. Is this in netural or under load?? When you pump the primer bulb before starting does it get nice and hard or does it seem to keep taking multiple squeezes?? You say it idles OK so that takes low speed charge coils out. Is it sneezing in this in between throttle operation? Your list of problems may be as long as the boat in feet. At which point (RPM) does it die?? Whats the point at which the engine dies?? Anything above idle? More input can dial me into a solution

The boat was installed without a permanent tach, so RMP's are not an option.

If you quickly go from in-gear idle to WOT, the boat runs like it should.

If you slowly, but steadily move the throttle towards WOT, then the boat will bog down and stall .

Fuel restrictions is not a problem. The bulb takes 1-2 squeezes to get hard and does not suck down when it is running.

Again, if the engine is tilted up slightly, it will not bog down and stall, but only slight bog down then seem to surge when the highspeed jets kick in.

[dorf]

OK....from my limited experience with 2 cycle jet skis it seems to me that one or more cylinders are running LEAN.

If you have a choke, pull it out when the stumble occurs(trasnsitioning to WOT). If it improves cylinder(s) is/are lean.

If not then it is rich.

You will be able to tell from the burble/noise when all is running OK.

Be sure that the timing is set correctly first.

Adjust the pilot screws(each carb) counterclockwise in small increments one at a time, then run it.

This may be over and above this discussion but an additional item (FROM JET SKIS)Piston Wash is important. Piston Wash is observed by looking in the spark plug hole for clear areas about the size of your fingernail around the ports. If none or very little wash the cylinder is lean. If wide like your thumb it is rich. It is better to be rich than lean. If lean you will burn a hole in the piston(hot-no cooling fuel)

Additionally the color of the plug, down inside will tell how a cylinder is working.
Yamahalube says it is not synthetic but my obervation tells me it is at least semi-synthetic 'cus it burns like synthetic---Not like regular 2 stroke oil.

If necessary, I'll try to find pictures to describe Piston Wash.

Just do not rely on the Yam's mechanics alone.---It ain't their boat----

I don't know/remember if you have a Clymer Manual or not but it has descriptions pictures and procedures---Good Book---

Cheers !!!

[margaritaville]

OK....from my limited experience with 2 cycle jet skis it seems to me that one or more cylinders are running LEAN.

If you have a choke, pull it out when the stumble occurs(trasnsitioning to WOT). If it improves cylinder(s) is/are lean.

If not then it is rich.

You will be able to tell from the burble/noise when all is running OK.

Be sure that the timing is set correctly first.

Adjust the pilot screws(each carb) counterclockwise in small increments one at a time, then run it.

This may be over and above this discussion but an additional item (FROM JET SKIS)Piston Wash is important. Piston Wash is observed by looking in the spark plug hole for clear areas about the size of your fingernail around the ports. If none or very little wash the cylinder is lean. If wide like your thumb it is rich. It is better to be rich than lean. If lean you will burn a hole in the piston(hot-no cooling fuel)

Additionally the color of the plug, down inside will tell how a cylinder is working.
Yamahalube says it is not synthetic but my obervation tells me it is at least semi-synthetic 'cus it burns like synthetic---Not like regular 2 stroke oil.

If necessary, I'll try to find pictures to describe Piston Wash.

Just do not rely on the Yam's mechanics alone.---It ain't their boat----

I don't know/remember if you have a Clymer Manual or not but it has descriptions pictures and procedures---Good Book---

Cheers !!!

Dorf,
I have to rely on Yamaha mechanics because it is under warranty and even though this might not be a warranty repair, if I do something that is not in the user manual, it explicitly states that the warranty will be voided.

The choke is electronic, but there is an neurtral advance lever on the remote control, but that is locked when it is in gear.

[dorf]

OK---I understand, and your engine does not have pilot screws(like mine)...

Post what happens.

Cheers!!!

I'm really thinking you have a carb problem. You said that you had all carbs replace. I'm assuming it ran fine after that. I'm not a big fan of Sta-bil and if you have the bad quality of gas as I do here in N.E. with the ethanol and it sat in the summer heat (gases biggest enmy). Factor in the carb replacement by your yam tech ( did he flush fuel lines / fuel pump )? It dosen't take all that much to clog up. Your floats can be hanging up which in some situation the engine will run better when either leveled up or down using trim. I have seen the little black rubber plugs in the bottom of the carb blocking the low speed jet hole (which are supposed to be there) get all gummy from ethanol and clog up carbs. If Sta-bil is an alcohol base stabilizer it only adds to the problem, although I'm not sure if Sta-bil is alcohol based.