Engine cutting out at lower RPMS

[Vindawggy]

Hey all,
Quick question engine related. First off I’m running a 2001 Yamaha 115 4 stroke on my 2001 1801. The boat is new to me. Don’t have a hard time cranking the motor over or holding an idle but it seems like when I kick it into gear either forward or reverse it often cuts out. This happens more often after a longer run and the engine is on the warmer side. I usually run the motor between 4000rpm and 4300rpm when under way. Soon as I back off the throttle after my run it cuts out. It will always crank back up but then cuts out when I kick it into gear - basically having a hard time at the lower rpms which is annoying when I get the ramp and I’m loading up the boat or I’m fishing.
Thanks in advance for any words of wisdom.

 

[warthog5]

Sounds like idle in gear is to low.

 

[knotflying]

I assume it has fuel injectors? Perhaps the injectors? There is also an idle air solenoid, perhaps that is malfunctioning.

 

[GoodChance]

Adjust the throttle linkage at the motor end so that the engine idles at 700-800 rpm. I'd venture a guess that you are currently set to idle at 600 rpm

 

[Vindawggy]

Adjust the throttle linkage at the motor end so that the engine idles at 700-800 rpm. I'd venture a guess that you are currently set to idle at 600 rpm

Thanks I’ll check that out and follow back.” Up.

 

[parrotfish]

I had the same problem for several years. After changing fuel filters, vst filter, a wiring harness and going thru 3 mechanics it turned out to be the throttle position sensor indicator was bad. Changed it out and has not died since.

 

[Vindawggy]

Thanks!

 

[WestCoastNut]

I chased down a similar problem on my Yamaha F200 a couple years ago. Did the same things Parrotfish did and eventually solved it by replacing the idle air control valve. If I recall, it was fairly easy to determine it was bad, once I learned that part existed. I had the same symptoms, engine would die but only after running for awhile, and only at low rpms. Of course it’s about a $400 valve, for a marine grade version.

 

[Fishaddict]

I had the same problem for several years. After changing fuel filters, vst filter, a wiring harness and going thru 3 mechanics it turned out to be the throttle position sensor indicator was bad. Changed it out and has not died since.

My friend’s 150 4st Yamaha would not go on plane and so called Yamaha dealer upstate NY ended up changing injectors, sending power head for rebuild claiming it’s valves problem. It ran just as poor. It ended up being this part for 27 bucks. For newer engines(mid 2000 on )you can use Yamaha diagnostic software.

 

[chas650r]

on injected motors that are equipped with a idle control valve (icv) the idle speed is not controlled be throttle position . at idle the throttle body is completely closed and and idle intake combustion air volume is bleed through the idle control valve driven by the ecu. this is how you get consistent idle at different air densities and temps ect. as you might guess the opening in the valve is quite small and must be free to move accurately . its common for the valves to carbon up and can sometimes be cleaned easily saving the replacement cost. as noted above the the diagnostic software if equipped is the place to start and may show a problem with the icv if that's the issue.

 

[Vindawggy]

Adjusted the idle to 750 a while back and now she runs like a dream! Thanks so much for the help!