Pro XS Motor mount option

[fuelleak]

Really would like to change out my motor mounts on my 2019 Pro XS 250. Motor shakes so hard in rough water that you feel it through the whole boat. If I turn around and look at motor it is bouncing fore and aft pretty violently. Kinda scary. The fact that it is shaking the whole boat is too much to want to continue running this boat hard in rough conditions. Is there an alternative stiffer kind of mount that will fit this engine? What kind of costs would be involved if firmer mounts are available? Serial # 2B571507

[Brewerbass]

Is it on a jackplate?

[fuelleak]

Yes it is but its not the jackplate from what I observed. Ive watched motor while someone else drove, sure looks like the motor mounts to me. Been in another boat with same motor and his bounced just as bad shaking the boat.

[howieranger]

I would think that installing stiffer mounts would transfer more shake and vibration to the boat.

[fishnfireman]

I've read several who have the same issue.
No complaints from the R motors which have stiffer mounts.

[sblnchrd]

I have a 2020 300 pro xs on a z21 NITRO 12"ATLAS hydralic jkp and I notice the same thing this motor really shakes a lot in rougher water more so than my 12 250 pro xs. ive got a slight porpise problem on top end 70-75 I think its the motor moving to much definitely not the jackplate

[fuelleak]

Ive asked my partner to turn around and make sure that motor is staying put. He normally turns back and says its bouncing pretty good. So far it hasn't loosened any through hull or through jackplate mounting bolts. It really feels to me that that bouncing would really stress out the mounting bolts so I check them regularly.

[Brewerbass]

I asked about a jackplate becuase i have a couple friends that run atlas plates and their motors move alot and the movement is from the atlas plate

[EuropeanAM]

I asked about a jackplate becuase i have a couple friends that run atlas plates and their motors move alot and the movement is from the atlas plate

Quite commonly find that the bolts securing the front/spacer portion to the back (jackplate) portion are not being re-torqued and have become loose. Make sure these are being checked regularly.

There is no cost-effective method of changing over the mounts to the Racing mount setup. While it "could" be done, it should NOT be attempted unless MERCURY has advised to do so.

The mount system used on these engines is a COMPLETELY and UTTERLY different design than the previous models. The dampening and sound reduction changes are significant- but indeed the engine does move considerably if running at high-speeds in rough water. Often arguably "too fast in too rough" a water.

Previous models with harder mounts would sometimes break mounts/mount clamps under such circumstances.

[angleiron]

If this was a jackplate bolt issue I very much doubt you are going to see any movement coming from the jackplate with 500 pounds hanging on it...more so at idle. There is a reason why the R engines have the stiffer mounts because in reality there is not that much difference between the R engines and the XS motors...very minor. People who are going to run a R engine are doing so on high performance hulls that need enhanced boat control...and what the XS and regular 4 strokes are getting are general motor mounts for comfort (less vibration) for the masses. For as many that will complain about the excess movement the fact that you have to look back to see the movement versus feeling it through the steering wheel goes to show why things are the way that they are. The Pro XS motors should have came with the R engine mounts...

[fuelleak]

angleiron, i agree! i feel it through the hull!

[EuropeanAM]

angleiron, i agree! i feel it through the hull!

With the utmost of respect intended... how are you able to differentiate the vibration of the boat on the waves vs. the engine moving within the range of the engine mounts?

[low slung cruiser]

I can feel it strong in mine...
it feels almost like the hull is flexing... noticed in within first 10 mins of running the day I repowered...
since then(94hours) I have learned how to change my trim to limit this...

if there was an upgradable mount to cure this, I would do it...

[sblnchrd]

i agree i can also feel the vibration in the hull my z21 porpoises on top end 70-75 hull goes down bobs back up u can feel the engine bob as its trying to lift hull very frustrating on. a $73000 boat

[low slung cruiser]

i agree i can also feel the vibration in the hull my z21 porpoises on top end 70-75 hull goes down bobs back up u can feel the engine bob as its trying to lift hull very frustrating on. a $73000 boat

i dont know of this feeling...
what i was referring to is when you are running 30-50 in good chop, the motor has some forward and rear direction(aft) movement...none left and right...it does appear to have been designed this way for a shock absorber, however, my fear is the long term destruction being done to the mounts...

i have considered adding one of those mid section safety ropes just so if the mount ever fails it will keep the motor back there and not on the rear deck...

[fuelleak]

Don, it doesn't take a genius to feel the motor shake the hull. This bouncing of the motor is definitely putting stress on the mounting bolts, jackplate and transom. It is a very unusual feeling to have a boat being shaken in time by the motors mounts flexing so extremely. You can turn around and see that the motor bounce on those soft mounts and the reverberation go through the whole hull. I am in agreement with low slung cruiser that it feels like its flexing the hull. Like I said, both mine and my partners V8s do it.

[mikesxpress]

Gary how about a video??

[fuelleak]

mikesxpress. Ill try, not sure it will translate to what you feel but it will definitely show the motor bouncing fore and aft, doubt it will show what you feel through the seat of your pants. As an example, imagine you have a long flexible heavy soft rod in your hand and your holding it straight up. Someone pulls back on it while your trying to hold it stable and they then let it go and its back and forth bouncing forces flexes your wrist, arm and shoulder back and forth as you try to stabilize its movement. Now do the same thing with a more rigid rod and see how quickly you can gain control of that rod. Thats the same kind of force you feel through the whole hull as you travel through chop and waves. Im obviously not alone on this issue! Maybe we are all nuts but these forces translated through the hull do not feel normal. Reducing motor movement will reduce the forces applied to the hull and hardware. Im sure there is a happy balance between too soft and too stiff but Merc's current mounts at least on my boat seem way too soft. Still haven't found out if I can buy stiffer mounts or not!! And yes to Don, Checking bolt tightness was the first thing I did when I felt this movement.

[mikesxpress]

I've had mine for over 2 years on a Z21 Intracoastal Ranger. I know it shakes way more than the Opti it replaced as I can see it too. It just doesn't transmit it thru the battle ship and soft ride seats (Ranger SRS) to my frame.

[fuelleak]

Time will tell mikesxpress if this downward and upward force takes a toll on anything. Motor mounts are like shocks, compression and rebound should be controlled for a smooth ride. this downward force and upward force of the motor on a stiff hull like Falcons really shows itself as this movement through the mounts moves the hull up and down. Ill let you know if this motor ends up in my lap or Im just a bit over analyzing things. Never felt this in any other boat.