1999 Yamaha 130 BETO - Minor problem.

[Speedcop]

My 1999 Yamaha 130 BETO has had minor problems in the past. Fuel pump diaphragm, timing etc.
I acquired the Yamaha 115-130 service manual and set it up according to factory specs.
(Carbs, Timing etc.) It starts and runs fine now. Fuel consumption is quite good, little or no smoke.

I have just one question...

I use the boat about twice a month in a fresh water river. With no passengers and only safety equipment on board, and on smooth water, at WOT it goes great! – Fifty + miles per hour at 5,600 revs.
From idle and in gear, if I open the throttle fairly quickly to take off, it has a slight hesitation (no misfire), before full power comes in, and then it takes off like a rocket. If I open the throttle normally, it goes fine.
I understand the motor is a 2 stroke and will be a bit rough, but from idle (750 rpm), up to about 1500 rpm the motor is rough and vibrates, although all cylinders are firing. After that it's smooth as a four stroke! Is this normal or...?

I did the whole setup according to the Yamaha service manual from the dial gauge on piston set up, sync and link, throttle cable, right down to idling adjustment and idle mixture screws at 9/10ths out from fully closed. Carbs have been stripped and cleaned, reset according to spec, timing and carb sync done. Fuel filter and water separator changed for new ones. Cleaned and flushed fuel tank. New NGK plugs. Compression test within spec.
All electrical connections checked and cleaned. Voltage reading = 14.8v @ 1000 rpm at the battery.

The boat is a fiberglass Challenger 16ft mono hull. New Yamaha 13 X 19 stainless propeller.
The motor has done 273 hours. Fuel is 93 octane unleaded (no ethenol), Lower octane is not available here in South Africa. I’m using Fuchs TCW-3 Outboard Oil.

Could someone from the panel throw some light on this? - It would be greatly appreciated.
Thanks – Dennis.

[Speedcop]

1999 Yamaha 130 BETO

My 1999 Yamaha 130 BETO has had minor problems in the past. Fuel pump diaphragm, timing etc.
I acquired the Yamaha 115-130 service manual and set it up according to factory specs.
(Carbs, Timing etc.) It starts and runs fine now. Fuel consumption is quite good, little or no smoke.

I have just one question...

I use the boat about twice a month in a fresh water river. With no passengers and only safety equipment on board, and on smooth water, at WOT it goes great! – Fifty + miles per hour at 5,600 revs.
From idle and in gear, if I open the throttle fairly quickly to take off, it has a slight hesitation (no misfire), before full power comes in, and then it takes off like a rocket. If I open the throttle normally, it goes fine.
I understand the motor is a 2 stroke and will be a bit rough, but from idle (750 rpm), up to about 1500 rpm the motor is rough and vibrates, although all cylinders are firing. After that it's smooth as a four stroke! Is this normal or...?

I did the whole setup according to the Yamaha service manual from the dial gauge on piston set up, sync and link, throttle cable, right down to idling adjustment and idle mixture screws at 9/10ths out from fully closed. Carbs have been stripped and cleaned, reset according to spec, timing and carb sync done. Fuel filter and water separator changed for new ones. Cleaned and flushed fuel tank. New NGK plugs. Compression test within spec.
All electrical connections checked and cleaned. Voltage reading = 14.8v @ 1000 rpm at the battery.

The boat is a fiberglass Challenger 16ft mono hull. New Yamaha 13 X 19 stainless propeller.
The motor has done 273 hours. Fuel is 93 octane unleaded (no ethenol), Lower octane is not available here in South Africa. I’m using Fuchs TCW-3 Outboard Oil.

Could someone from the panel throw some light on this? - It would be greatly appreciated.
Thanks – Dennis.

Could somebody please comment? It would really be appreciated.

[rodbolt17]

did you check the carb pick up timing?

[VictoryBW]

Sounds like your floats in carbs are not adjusted properly, if your float bowls dont have enough fuel in them on fast throttle it will starve the motor causing hesitation, and if you go slowly the fuel pump can keep up with the demand of fuel and it will in crease speed without hesitation.

[ausnoelm]

did you check the carb pick up timing?

Do this first, do not start pulling things to bits yet.

[99yam40]

I believe they are speaking of the ability of the timing to start advancing at same time or right before the carbs start opening the throttle plates.
It is important for this to happen. The service manual should have the procedures for all of this.

If that does not help you might back out the pilot screws just a little but still within the specs in service manual to help in the transition off of idle

[Speedcop]

1999 Yamaha 130 BETO - Minor problem.

Thank you to Rodbolt, 99yam40, Ausnoelm, VictoryBW for your replies.
I have a question for rodbolt. Re carb pick-up timing, the service manual on page 3-11 shows a drawing of the throttle cam aligning with the throttle roller.
According to the drawing, the roller is touching the cam.
Now I recall one of your earlier posts, saying that the two should not touch?
Could you clarify this for me?

Thanks 99yam40 for your knowledgeable input. I do understand the importance of the timing of the ignition/fuel, but as stated above, I'm not altogether sure if the service manual is correct as shown.

VictoryBW, thank you for your valued input. Your advice definitely makes sense. I have stripped and cleaned the carbs and set the floats according to spec. - However, someone once said that if you tow the boat and motor on a trailer after running the carbs dry or draining them, the floats will bounce around and may affect their settings!
Is this true, or an "old wives" tale?

I'll wait for comments and only then tackle the anomaly further.

Thanks Guys, the input is really appreciated

[Speedcop]

Yam 130 Minor problem?

Thank you to Rodbolt, 99yam40, Ausnoelm, VictoryBW for your replies.
I have a question for rodbolt. Re carb pick-up timing, the service manual on page 3-11 shows a drawing of the throttle cam aligning with the throttle roller.
According to the drawing, the roller is touching the cam.
Now I recall one of your earlier posts, saying that the two should not touch?
Could you clarify this for me?

Thanks 99yam40 for your knowledgeable input. I do understand the importance of the timing of the ignition/fuel, but as stated above, I'm not altogether sure if the service manual is correct as shown.

VictoryBW, thank you for your valued input. Your advice definitely makes sense. I have stripped and cleaned the carbs and set the floats according to spec. - However, someone once said that if you tow the boat and motor on a trailer after running the carbs dry or draining them, the floats will bounce around and may affect their settings!
Is this true, or an "old wives" tale?

Thanks Guys, the input is really appreciated

I'll wait for comments and only then tackle the anomaly further.

[99yam40]

I do not know if that 130 is any different than my C40 but Rod has told me in the past to have the roller just off the cam, maybe .010 or .020 away.
As far as running one of these muticarbed motors until it dies trying to get all the fuel out of carbs( running carbs dry) , it can not happen.
One or more cylinders will be running lean( low on fuel) long before the others will, and none will suck all of the fuel out.
Which leaves some fuel left in there to evaporate even more quickly and leave residue.
Best not to try. Keep them full and run often so none evaporates completely to leave residue on bowls.

They do have drains on bowls if you feel like you have to drain them,

I would not worry about floats bouncing around messing up settings when bowls are empty if you do drain them. I think that is BS myself

[rodbolt17]

float bounce is a wives tale, usually told by untrained persons that have no other explanation yet have to say something.

there are typically three stages of ign timing.
timing at idle.
timing at the point the cam picks up the throttle roller and timing at WOT.

some engines use a different setting for idle and pick-up. some its the same.

that's about the only good reason I smoke.
when someone comes up with a really stupid question/statement it gives me time to come up with a response or stifle the giggles.

so if your ever in the shop, watch out when I light up .

[Speedcop]

1999 Yamaha 130 BETO - Minor problem.

float bounce is a wives tale, usually told by untrained persons that have no other explanation yet have to say something.

there are typically three stages of ign timing.
timing at idle.
timing at the point the cam picks up the throttle roller and timing at WOT.

some engines use a different setting for idle and pick-up. some its the same.

that's about the only good reason I smoke.
when someone comes up with a really stupid question/statement it gives me time to come up with a response or stifle the giggles.

so if your ever in the shop, watch out when I light up .

Thanks 99yam40 and Rodbolt!
Rodbolt, I love your sense of humour!!
Re the floats...that's about what I figured!
The reason I ask for your advice, is that I bow to your superior knowledge of everything Yamaha!
If I ever visit your shop, I'll be sure to bring you a pack of smokes!
Kind Regards,
Dennis.