Boat Pulls Left....

[PreciousMetals]

I have metioned this to a couple of people, but thought iw ould post this here. In summary, at very similar RPM readings my boat in general wants to pull left and i have to keep the wheel turned to the right to get it running straight. Anyone had similar issues, and how did you fix it?

Thanks in advance....2010 242 LS

 

[steined]

I've never had this issue but I would place the gear lever in forward and measure the height of each thrust gate relative to the jet nozzle. If one is too low it could cause a slight amount of drag. Does your boat idle well in neutral or does it tend to want to spin? Mine is pretty well neutral with very very little tendency to creep slowly forward.

I recall having to steer right a bit while boating in a stiff wind but not general cruising. I'll try to pay attention the next time I'm out.

 

[Bruce]

@PreciousMetals, didn't you say that one of the jets was opening further than the other?

 

[itsdgm]

Has it always done this? Or has it just started acting up?

Our boats by their nature want to turn left. It has to do with the rotational force of the engines. To counteract this, Yamaha has installed different pitched impellers on each pump. Some models are more evenly matched than others.

If it just started acting this way, it's usually caused by uneven thrust. There could be a few different things causing that. Could be that there's something in the pump, or simply that the engine on the week side isn't reaching full rpm.

 

[rkluck]

Another thing to look at is to make sure the nozzles are both pointing straight and one is not off a little.

 

[Gumbeaux]

There are other posts about this...including a thread I started. I am still chasing it but it's not terrible anyway...have not invested much this year investigating...
My thread:
https://jetboaters.net/threads/boat-pulls-left.1428/

 

[Cobra Jet Steering LLC]

In the past people have discovered the left side ride plate protruding slightly below the hull surface causing a left hand drag on the hull. So look at that and make sure that isn't the issue.

 

[Craig]

While looking for something else I came across this on the web. Lots of interesting information on this webpage, including an explanation of why our boats steering pulls to the left.
http://www.groupk.com/yjetboat.htm

Excerpt from the page explaining the tendency of our boat's steering to pull to the left...

" All technicians that build high performance PWCs quickly learn a few fundamental rules about PWC pump function. As you engage a jet-pump driven watercraft in to a high-speed (power-on) left hand turn, the engine/pump gets very heavily loaded, and engine rpms are usually “pulled down”. However, making a right hand turn at exactly the same speed results in no rpm loss at all … and often results in an rpm increase, often accompanied by mild cavitation.

The reason for this phenomenon is that the entry angle of water coming in towards the impeller has a big effect on how well the pump get “loaded”. In left hand turns, the water comes toward the prop at an angle that very effectively “loads” the pump with water, and allows for very minimal “cavitation”. A hard right hand turn has exactly the opposite effect because the water is coming in toward the prop in a way that is very “unfriendly” to pump loading. Anyone who has driven a single engine Exciter 135 will experience this phenomenon in a big way. Using aftermarket impellers with a better blade/hub design can greatly reduce the cavitation experienced under all conditions …including in right hand turns. But even the best designed prop cannot eliminate right-turn cavitation altogether.

Twin Engine Pump Loading

The phenomenon described above affects the twin motor jet boats in an entirely different way. The water intake surfaces on the bottom of twin motor hulls are on angled surfaces on each side of the hull. This “angled water entry” gives an effective entry angle that mimics the pump loading of turning the boat. This means that (while driving in a straight line) the drivers side pump (starboard) is receiving water at an angle that mimics a left hand turn (thus loading the engine rpms down). At the same time, the passenger side (port) impeller is receiving water at an angle that mimics a right hand turn (resulting in higher rpms and a closer cavitation threshold). This is why the left (port) motors of most twin-engine Yamaha jet-boats tend to run higher rpms than the right (starboard) engines.

Getting past the whole theoretical aspect, the functional result is what’s important.. Because of the phenomenon described above, the right side pump is generating more actual thrust than the left pump at any given rpm. This causes the steering wheel to constantly be “tugging” toward a left hand turn, and at the same time causes the left side engine to rev higher than the right engine in order to generate the same thrust."

 

[Cobra Jet Steering LLC]

Interesting however He was experiencing a serious left hand pull and this also occurred in deceleration not just acceleration.
Thus leading me to believe it was drag from the hull etc. like a power hook or something causing excess drag on the left side of the boat.
Add that to the effect you just described and one can understand how he was afraid to go faster than 35 mph since the pull was enormous.
I would think the manufacturer has an obligation to make it right with as little inconvenience as possible to the consumer. I don't see the dealer being the responsible party in this situation.
Federal laws give consumers an implied warrantee, I would also think the manufacturer has a hull warranty.

 

[Craig]

Certainly not implying that what I listed was the reason, just thought it might be relevant to the thread and putting it out there (since I didn't stay at a Holiday Inn Express last night..). I'm very new to these boats and don't pretend to think I can troubleshoot the OP's problem, just trying to offer information that may (or may not) be relevant.

 

[Cobra Jet Steering LLC]

My bad I actually mixed up the threads I was actually referring to this one.https://jetboaters.net/threads/new-gts-187-here.2697/