PRO XS VIBRATION

[buttermilkbiscuit]

I gotta pro xs that, when you're fast idling up to-on plane speed, seems to shake an awful lot. Prop is spinning true, so nothing bent. I'm use to yamaha's, and someone told me that the pro xs has solid mounts, which could make a difference. It just seems a little excessive to me. Going fast, at regular speed, you can't tell anything. Fast idle is where it's worst.

Anyone else's do this? I've had three of these motors since they came out, but not in the last year or so. I can't remeber any of them doing this.

thanks!

[EuropeanAM]

Specifically WHICH ProXS do you have?

Precisely what RPM range is this occuring in?

This information will be very helpful.....

[buttermilkbiscuit]

2007 20" shaft, on a stratos 201. 250 hp.
starts at around 2000 rpm

thanks

[EuropeanAM]

I would be remiss to tell you to "ignore" this. Yes, it could simply be the nature of the engine (combined with the setup), but there are also a multitude of other possible "causes".

I would suggest having it checked out. Confirm the basics- including SPARK PLUGS (IZFR6J, gapped at .044").

I would also recommend that the engine mounts be checked for fatigue, wear, or other problems.

[bassnthrough]

mine does the same, 300xs, 2008, had coils replace gaped new plugs myself, seems to be less when using better octane gas, 93-94 instead of 91 octane, no codes goes out of warrenty in Oct.

[buttermilkbiscuit]

The motor only has about 70 hours on it, so it should not be worn. it actually feels like the prop is off balance.....alot. But there is not one single nick on the temp/plus prop, and the prop spins absolutely 100% true, with no wobble at all, like the prop shaft was bent. I'll check the plugs, and I even thought about the flywheel, as I assume it acts like a harmonic balancer on a car engine. I've been using 87 octane gas. No one has ever told me to use higher.

thanks guys

[EuropeanAM]

There would be no harm in you trying a tank of MID GRADE (89 octane) fuel. In some cases (especially in the warm summer months), we do find an improvement in low-RPM operation by stepping up the octane SLIGHTLY (one grade).

Simple enough for you to test.....

[jclark408]

trim all the way down takes the hydraulic cylinders out of the equation........they offer some cushioning........just bump the trip up ever so slightly and it will stop

[hoytkimbershimano]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by jclark408 &raquo;</td></tr><tr><td class="quote">trim all the way down takes the hydraulic cylinders out of the equation........they offer some cushioning........just bump the trip up ever so slightly and it will stop </td></tr></table>

This is definitely true in my case too!

[TubeCarz]

The older ones do it too . Seems that they run really rich just off of idle .
Bumping up the TPS will dump in more fuel along with timing .. so maybe a better alternitive would be to to drill a .100 hole in the butterfly to lean it out to where they dont 4 stroke at fast idle .
Trimming to a weird angle or jacking the motor up to where the prop is hiding behind the transom and kind of freewheeling are band aids to the real problem .. Ill bet the plugs are soot black ... and at that point it dont matter what kind you use .

[EuropeanAM]

DO NOT drill holes in the butterfly!!!! This will result in a lean mixture ACROSS THE BOARD.

We often find that the off-idle performance problems are NOT a rich mixture.... it's usually LEAN (and in many cases, lean due to soot and carbon buildup in the direct injectors.... often from lack of using Quickleen regularly).

95% of the engines we see exhibiting this symptom clear up when the direct injectors are cleaned, and clean spark plugs are in place.

[2500]

one thing we have found has been if you have the PVS holes in your prop and say the holes are all plugged but 1 (3-blade) it dumps exhaust out and the prop can shimmy or feel out of balance, on (4-blades ) same thing. it has happened twice with some local guys. try to adjust holes to be even with plug sizes.

[Props4u2]

trim all the way down takes the hydraulic cylinders out of the equation........they offer some cushioning........just bump the trip up ever so slightly and it will stop


I agree with this 100%.

Every 3.0 & 3.2L I have ever ran does this.

I have also seen different boats do different things, for instance, if the boat is not on plane it may be cavitating or ventilating the prop causing an out of balance/wobble feeling.

[hoytkimbershimano]

The comment on the pvs plugs is interesting too. Mine definitely shakes a little more than it used to. I have a trophy plus and my pvs plugs are not symmetric. Mainly because the shop didn't have the number I needed... I have 2 closed, one big, and 1 small.

Interesting

[TubeCarz]

Don ,
I was under the impression that a dirty injector wil tend to have a poor spray pattern and / or leak while closed . I guess that can also clog up too .
I think what is being discussed here is the 2000 rpm vibration that most feel while running at a high idle for miles at a time like we have to do here in Florida because of those &^%$#@ sea cows.
My 3.0L when lean will sneeze , lean pop and split the bleed lines ... yes mainly the ones under the starbord side electronics plate.
I still think that the shake comes from running overly rich (hence the carbon build-up you mentioned) at this part throttle speed. Once I was able to get mine to run in the 600- 650 degree EGT range ( @ 1200 - 1800 rpm), my shake has all but disapeared.
As far as introducing a little air into the plenum area by use of a bleed hole. Stock carb motors have ben that way for years. To do it one either a two or 4 shutter will only be effictive at these low opening angles. If you are able to make the air turn ang go thru the hole once the resistance to turning becomes greater than just passing along the blades surface and spilling into the venturi beyond quarter throttle ... let alone being at 90* to the hole at WOT .. then I know of some cyl head porters that would love to give you a job ...
The direct injection stuff is a little too new for this old dog ... but I understand that (much like a diesel operates) to check for a broken reed on a Opti .. you can take the throttle body off the motor while it's running and look down the plenum for any reversion ....
My point being , since we cant hook up a lap top and tune the shake out of them with fuel and timing maps while running .... sometimes we have to fool the system into working as a whole ...

[jayfaro]

My 250XB/Bravo1 Dual PVS will shake/wobble while idling around. The one thing I found, as mentioned by several, is that if I bump my trim up a little, the vibration/wobble goes away completely. I normally trim up anytime I'm idling to get the exhaust out of the water so it doesnt carbon up the motor, but when i would shut down to idle under a bride, i noticed it. Hopefully, this will work for you as well.

[EuropeanAM]

Charlie:

Can't say that the vibration referred to in this post "is, or is not" prop related, or injector related. Not enough information "hands-on" to form an opinion.

Although both the EFI and Optimax are still "suck, squish, bang, blow" speed-density engines, there's very little in common between them other than that.

Fuel is delivered on the Optimax in an "atomized" format, directly atop the piston during the compression stroke (at the moment the ports are covered by the piston). This means that the engine can still "fire" fuel to some extent- EVEN with a failed reed, without "backfiring" through the crankcase. Doesn't mean it will run well- but it will run....

Dirty direct injectors will often develop an irratic spray pattern- I've even seen some that would clear up an "idle-miss" by simply rotating the injector 5 degrees (apparently a stray spray stream hitting the spark plug grounding arm and disrupting the correct delivery of fuel).

This is one of the reasons why regular use of Quickleen is critical on ALL Optimax engines.

[lwlittle]

I had added to another similar post. I have a 225 por XS on a 2005 Chap 198 and have the exact same problem. I run Quickleen and 89 Octane fuel. Trimming it up at fast idle makes some difference but the vibration doesn't go away totally. As soon as I am on plane it smooths out. I ma getting close to warranty expiration. Should I be concerned and get it in for a checkout. I have only had the boat 2 /12 years and I will have to check on the spark plugs but it doesn't necessarily feel like the enigne is mis-firing to me.

[EuropeanAM]

Leonard:

It's never a bad idea to have this sort of thing checked, if for nothing else than some peace of mind.

If you haven't replaced your plugs.... now is likely a very good (and perhaps past-due) time.