Yamaha 2004 150HPDI lower mount bolts

[Capt. Yakes]

For the first time in 9 years due to one side of the cover falling off the lower mount I was privy to seeing the main lower mounting bolts have accumulated a considerable amount of corrosion. Unfortunately this is not an easy fix due to the fact that on this particular model year the lower mounting bolts are installed with the head of the bolt to the inside of the motor mount. The fix requires removal of power head...I considered getting the nuts off and then pushing the bolt in to be able to cut off the head and then installing in reverse but Yamaha techs have advised against this move. The kicker is that Yamaha is out of stock on these bolts and they are back ordered from the supplier. Made calls all over to no avail. I am told these are coated stainless bolts and not solid stainless not sure why Yamaha would be making that decision on a saltwater motor???

Has anyone out there experienced this situation with corrosion on the bolts. I find it interesting that these bolts are out of stock and the possibility that situation is not unique to my motor.

Might have to fish it the way it is for now as the MAKOs are snapping.

Opinions appreciated

 

[charlesretired]

Remember the tsunami that hit Japan ?? Did you try the used parts suppliers ? I have good success with Marine Supply in Gulfport Ms, Ph 2288229451 or Boats.net

 

[DaleH]

I remain confused as to exactly which bolts you are referring to. You say "main lower mounting bolts". And you allude that you saw them only with the side lower pan removed ...

Be that as it may, Yams were notorious for not using SS hardware when they copied the OMC design - bolts and components. Eventually this led to their release of the Saltwater series, where all they did was change the problematic carbon bolts/parts to be made of SS, e.g., the main steering rod and shift rods, which used to be plain ol' steel.

FWIW my brother runs twin Yam 1987 150XP 2-strokes and while yes - he did incur the cost to replace the shift rods and steering rod (that connects to the Seastar hydraulic steering piston) ... that's all he's had trouble with. Saltwater use to boot!

 

[windknotnc]

I know exactly what you are talking about. These are the lower engine mounting bolts just above the cavitation plate. They have a cover on each side and a series of rubber bushings that absorb the engine vibrations. Real beast to remove because of the corrosion. If you are mechanically inclined and don't mind the pain of removing the engine off the boat you may be able to do the job, but I could see it running $1000+ at a shop. How many hrs on the engine?

 

[DaleH]

Oh, those. I'll just say that in almost 40-years of boating I have NEVER, ever heard of one of them ever needing to be serviced or replaced.

 

[Capt. Yakes]

Yes, that is correct they are directly above the cavitation plate under the plastic cover.

The parts finally arrived and I am having a reputable dealer do the work and yes you are looking at around $1,500. If you never removed these covers for inspection you might never catch this corrosion. With no way other than to cut the bolt head off the powerhead does require removal.

I have seen a few other guys who have had this problem on the Hull Truth, keep your eye out and check behind your covers!