2009 Yamaha 30CV 2-stroke with intermittent splutter

[doodz666]

Gday guys

I'm not sure if the motor designations are universal, but I have an Australian-sold 2009 Yamaha 30CV. From the moment I bought it new I have had a constant problem.

I am able to start the motor fairly easily and it idles well. As I open the throttle to get on the plane, the motor splutters really badly. I wind back the throttle and it smooths out, then I open the throttle again. It will rev a little higher before spluttering again. It continues this way until after about thirty seconds of playing the motor this way I can finally open it up.

The motor will then run fine for the rest of the day. Even if it sits for a couple of hours and becomes cold again, I can get on the plane with no problem. The bulb remains hard as this happens and pulling out the choke has little effect.

I have experimented by taking off cold; idling for ten minutes before leaving the ramp; or motoring slowly for several minutes before opening up the throttle with no change. I have had the motor in for its first service and the mechanic said that they could find nothing after running it in the tank.

I contacted the yard that sold me the motor and was advised to wind the timing advance linkage out another two turns. I did this and it fixed the problem. However, after a few trips, the problem has returned and I am reluctant to keep winding out the timing, possibly just masking the real problem.

Has anyone come across this problem with the small Yamahas? Any ideas on what to try next?

 

[pongy]

Re: 2009 Yamaha 30CV 2-stroke with intermittent splutter

This is interesting because mine does exactly the same thing, Although mine is 1997 model 30HP
When first starting out for the day it is like it is dropping a cylinder, It will then clear itself and run fine
I don't know what the answer is but a friend of mine reckons the carbies need cleaning, he had a 40 horse that did the same thing and cleaning the carbies fixes it
His opinion is that it is due to the poor quality fuels we get here in Australia

 

[BaitThrower]

Re: 2009 Yamaha 30CV 2-stroke with intermittent splutter

Hi, I have a Yamaha 30CV, but it is a 2003 model, but I think they are pretty much the same motor anyway... I would make sure the motor is getting good fuel flow... Seems like it is being starved for fuel a little. Check for fuel blockages, ensure the primer bulb is orientated the right way and your length of fuel line is not too long. I have the tank up front on my 4.3m boat and had to install a larger primer bulb to get good flow... Also make sure when you prime the line using the primer bulb, to hold open the throttle a little as you squeeze the bulb.

Open the cowl and check fuel is coming into the fuel filter as you prime the line...

Let us know if you have any better success... I am in Australia too and purchase dmy motor second hand about 2 years ago. It had leaking gearcase seal when I got it so I fixed that, but otherwise it has run great! These motors do tend to run a little rough at idle and lower speed because of the single carburettor setup, and ensure you don't add too much oil to the mix. My 30CV is 100:1 ratio and i run at about 90:1. I had had idling problems and issues running 50:1 at times.

Let us know how you go!