Yamaha 55 forward and aft movement!

[SimonStDavids]

I have a manual tilt yam 55 and I have noticed that there is a bit of movement for and aft that seems to be getting worse.

This might not explain it very well, but when I tilt the engine I pull the engine in an inch or so before it starts to tilt up. The bracket is fixed rock solid on the transom so no movement there. It looks like where the bracket fixes onto the mid section is where the movement is.

Is this shot motor mounts or something just come loose? And how the hell do I get in there? Can't see any obvious bolts?

Any help much appreciated

[Xk59D]

sounds like the mounts are shot based on your description.

it can be quite a large job to fix this depending on the age of the motor and if any corrosion has set it (i.e snapping bolts)

if you are handy with a spanner then i would do it myself, if not you'll be spending quite a lot on labour unfortunately.

you should start by getting a service manual, some searching with your model year and or serial may get you a free one looking on google.

EDIT- this may give you an idea.

i would think you need No 46, 47, 48, 49, 51 (2 of), 66 and 72 (2 of) at a quick glance and that is hoping no bolts break off.

http://www.boats.net/parts/search/Ya...ER)/parts.html

please note, the above is only for a yam 55, i don't know what age you have so i only got it for explanation purposes.

hope that helps.

cheers

[spartacus]

Lower engine mounts are straight forward. It's the upper ones in the engine tray that are the pain. Soak well in Duck Oil Penetrating Release at least a week before attempting the job. Also knock first with a light hammer to break any corrosion in threads. Heat is good too if it feels like they're stuck fast.

I'd fit new bolts too. As soon as you torque the old ones they'll shear.

Use a light smear of marine grease on threads prior to fitting and don't, repeat, don't over tighten.

To get the amount of play you're suggesting, seems the mounts are well gone. Another sign would be excessive vibration, etc.

[phantom 19]

This job reminds me of the old Haynes Landrover service manual - "the user must decide on how much malfunction he can tolerate before deciding the overhaul the gearbox"

To do it the power head has to be lifted, this requires nine bolts to be removed which run through the leg and sandwich plate - they are hidden behind the lower apron panel which is held to the tray with four bolts.

Six of those nine bolts mentioned have a tendency to either snap of seize solid in the leg - they seize because they are a rolled thread so there is a void which fills with corrosion and the bolt is literally wedged in place. Duck oil or heat will not help with this.
If you manage to remove them all then the next problem could be the wall of the bolt hole where the water come up the leg and into the sandwich plate. This bolt hole can corrode and split the sandwich plate.

Then you have to remove the three bolts which hold the two upper shock mounts to the sandwich plate. Again without snapping any.
You can then undo the top shock mount through bolts... If they aren't seized in the steering tiller arm, and the heads haven't rusted away.

The lower shock mounts are easier, only two bolts per side to snap in the leg, then you can undo the through bolts ( these can actually be cut with a grinder).
Once all undone you can remove the leg/ sandwich plate from the bracket assembly, and replace the mounts. And at the same time replace the gearshift shaft with a new one because it is more than likely waisted away unless it's a very late "Origin" 55.

If you do manage to get that far without sticking it all in a box and putting it on eBay as spares, I have plenty of decent Al out new mounts removed from 90hps as I replace them with my own Acetal mounts for racing (55 and 90 share same leg units)

As a Yamaha engineer for more years than I care to remember I now wouldn't touch a 55 for repair due to the above potential problems! - shame as Yamaha built their reputation with that engine.

[Xk59D]

Originally Posted by phantom 19

This job reminds me of the old Haynes Landrover service manual - "the user must decide on how much malfunction he can tolerate before deciding the overhaul the gearbox"

hahaha, like it

i once had mounts replaced on a 55 yam, the mariner 55 one. it was £900 15 years ago, mostly labour.

in hindsight should have binned the motor but there ye go.

cheers

[phantom 19]

I think the 55's time has passed now. I don't think there are any left here in use, I can't remember the last time I saw one being used or heard their distinctive sneeze at idle.