2000 115 2 stroke STILL won't idle

All,

I am once again calling upon your collective expertise as I am at my wit's end with this motor. I purchased the YAMAHA rebuild kits for my carbs and went through both of them.. While there was some shellac in the floarts and on the jets, nothing was REAL bad like I have seen on some carbs before. However, I still soaked all the brass parts and blew out all the ports with compressed air. I set the float drop on each float according to the chart in the SELOC manual (15.5 - 16.5mm) and put it all back together with new gaskets.

I ALSO purchased a brand new fuel pump just to be on the safe side and installed it as well.

I backed the boat into the water expecting a triumphant start and clean idle and NOTHING... The motor turned over, but would not start. I had to use starting fluid to FINALLY get it to catch (it is oil injected so no worries there). It started, but only after being choked and the throttle being set to 3/4 full. Then it would NOT idle below about 1400 RPM.. Anything below this and the motor just dies.

I bumped the idle up on the carb to 1200 and let it sit for a while idling. I then backed it off the trailer and motored out of the marina and into open water. Above 2000 RPM, the motor ran smoooooth as 20 year old scotch, but anything under that and it stumbles and threatens to die.

I get back to the marina and line up to load on my trailer and the darn thing died and REFUSED to restart, in spite of the fact that I was choking it and setting the throttle in various positions. It took another shot of starting fluid to get it to start and of course it still would not idle. I put it up on the trailer and parked it and this is where I sit now.

I set all 4 idle mixture screws (per the SELOC manual) to 1-1/2 turns from lightly seated.

The low speed idle jets were cleaned well and shiny when I put them back in.

What should I try next? What could be causing it not to idle?

The primer bulb firms up, but after running for a while does not stay firm, but is not deflated either. This is on new gas and everything.

Does anyone have any ideas? I would sure appreciate the help because at this point I am at a loss.

By the way, the motor won't rev any higher than 4200 while underway. This is on a 25ft pontoon boat that is very heavy so this may be the cause of the lack of top end but I am not sure if this is related.

[boats.net]

Sounds like still have plugged jets or passasges in carbs or float valve stuck closed. Go through carbs again, remove float bowls and screw covering low speed jets, hold bowl up to light and see can see light through low speed jets. Double check all bowls are getting gas and check carb sync.

Clean Jets

Thank you for your suggestion, I truly appreciate it.

When I rebuilt the carbs, all 4 idle jets were clean an were held up to the light and passed light through. They were even inspected under high magnification I could see that the inside walls of the jets were clean and smooth.

I set the floats to the factory specs and tested each one by gently blowing into the fuel inlet on the carb while moving the floats up and down to ensure that the fuel flowed or stopped. After I pulled the boat from the water, I opened the float drains and each float drained about the same amount of fuel indicating to me that fuel was reaching each float bowl.

Today, I am replacing the fuel line all the way from the tank and adjusting the idle air screws to see if this has any positive results. If not, I truly don't know where to go from here other than the shop.

[Brandon Knott]

2000 115 2 stroke wont idle

Hello,

I am having the same problem with my 2000 Yamaha 115 2 Stroke. I can not get the engine to Idle. I have;

1) Replaced the oil water seperator
2) Replaced the fuel filter
3) Replaced the fuel pump
4) Cleaned the carbs

And still no luck...

I bought a 6 gallon portable fuel tank, did the mixture of oil and high octane and attached the primer to the engine. Once I replaced my fuel pump and filter I could get it to idle at 1000/1500 rpms for a min or so then it would shoot up to 2000 and then bog out...

I had the Carbs rebuilt three years ago because I couldnt get the engine to come down off plain (I would floor it, and had to choke it to get it into top gear) Once the Carbs were cleaned it eliminated that problem, but now Im stuck with what to do...

I dont want to purchase another Carb kit for $100 bucks if it needs a new one for $300+

I was worried that it may have something to do with the fuel lines or tank itself because of the integration of ethanol in the fuel used. I have used stabil religiously so I am hesitant on ripping everything apart for that...

On the other hand I hooked up the portable fuel tank and was still having the same problem so I am really lost and frustrated on what it could be.

I am curious to know if yours was ever fixed. Please advise

Brandon

[viking2010]

Did you get your issue solved. I went through the same experience and finally figured it out. Let me know if I can help.

[Duel_N_FL]

2000 Yamaha 115 2 Stroke Wont Idle Under a Load

I never did not see if this guys issue got resolved. I have a 2000 Yamaha 115 2 Stroke that will not idle under a load. I have the idle turned up to 1200 rpw and even then I have to baby it to keep it from stalling. Had carbs redone, non ethanol gas and new plugs by a so called certified mechanic. He said compression is good and motor is not tired as I was told by another mechanic. Auto oiler is still hooked up. It will slowly drop RPM when coming off plane to idle speed until it stalls and does the same when going into gear at idle.

The issue still persists and of course the mechanic will not return my calls. I notice that the exhaust is heavy with unburnt fuel as I see more oil in the run off when flushing. New plugs are quite black and wet but all look the same. This makes me think it is running rich. Have used Suzuki TW3 ever sense I have had it. Thinking about seeing if it does it when hooked up to a separate fresh tank of gas with premix and disabling the oiler. I was told that this would make it run even richer at idle though. The boat runs better than it ever has at top end. I am stumped.

[rodbolt17]

I would simply fix the fuel system and leave the oiling system alone.
but that's just me.

[Duel_N_FL]

2000 Yamaha 115 2 Stroke Wont Idle Under a Load

We have done just about everything that we can to fix the fuel system. I want to temporarily bypass the Auto Oil System to test with a tank of premix to see if that stops the fouling issue at idle. Unfortunately I cannot find a real good description anywhere on the web of how to do this.

[rodbolt17]

why not simply fix the fuel system???

why monkey unknowingly with a system that is working???

if the spark and compression are good fix the fuel system.

[99yam40]

guys this is an old thread
would be best to start a now one with all info and go from there