9.9/15hp top mount issues?

[crackedglass]

Over the past few years I've owned a dozen or more 1978 to 1992 model 9.9/15hp motors.
It seems that every one of these at one point or another needed the upper motor mounts replaced.
All were super clean freshwater run motors. The mounts just detached from their base.
What causes this or is this just a known issue with these motors?
I'm fairly easy on my motors, they don't get abused and are stored indoors.
I was using my 1990 9.9 on Sunday and one of the top motor mounts let go.
It wouldn't be so bad but you have to pull the power head, and lower unit to replace the mounts on these.

Between the cost of gaskets, new mounts, (I'd never just change one), and in most cases I put in at the very least a fresh wp impeller while the lower is off.
The gaskets alone were over $30 at the dealer, the two mounts were $85 each, and the water pump kit was $67. Its the first time for this motor but it seems every one of these I've owned has had those mounts either break or go soft. At nearly $300 in just parts it comes close to the value of one of these motors.

 

[kbait]

Re: 9.9/15hp top mount issues?

Common issue. The mounts are in the exhaust chamber, and get eaten away to failure over time. Fairly labor intensive job, and the mounts are $150 or so by themselves last time I bought 'em. Well worth it for my '81 15hp, as I hope to pass this awesome motor to my grandkids some day!

Leeroy (of ramblings fame) details how to make your own mounts for much less $. Search here: http://www.leeroysramblings.com/OMC_info/OMCinfo.htm Lot's of great info on the 9.9/15hp series... he's a wizard!

 

[gozierdt]

Re: 9.9/15hp top mount issues?

+1 on kbait's suggestion

 

[OptsyEagle]

Re: 9.9/15hp top mount issues?

Where would the problems start to arise if the bad or non-existent motor mounts are not replaced?

 

[boobie]

Re: 9.9/15hp top mount issues?

Power head could possibly fall off of the stern bracket. Those mounts hold it it on to your boat.

 

[slowleak]

Re: 9.9/15hp top mount issues?

I'm not sure I like the idea of the home made mounts, I've never had much luck with Gorilla glue and I would think that a better attempt at a home made mount would be a shock bushing from a car? Maybe even a urethane bushing?
I suppose you could even make up a new pair of aluminum mount brackets if needed, something that could be machined to accept a more common mount. It looks to me like the rubber would need to be hat shaped, so as not to be able to pull through?
Urethane is also more machinable than rubber.
I've probably got 10 of those motors here that need bushings replaced, they're a real problem when those motors start to age. Most that I've taken apart have the rubber just gone soft or torn away. I just figured it was years of exposure to exhaust and oil that killed them.
I do with the engineers who designed these would have had better sense than to have buried these bushings in such a way you need to just about completely tear apart your outboard to fix them.
I was reading a post on here the other day in regards to which was better the 9.9 or the older 9.5, I can say this, I've never had to tear down a 9.5 to replace motor mounts. In fact I don't think I've ever had to do anything but change the water pump and clean a few carbs here and there on the older motors.

 

[Haffiman]

Re: 9.9/15hp top mount issues?

The mounts are different for long shaft and short shaft. I always used the long shaft mounts even on the short shaft engines.

 

[the machinist]

Re: 9.9/15hp top mount issues?

SL, if you had looked at may Powerhead/Midsection article that KB was referring to & looked at the illustration how I secured the rubber grommet, you would notice that there was no glue used, just the grommet center shaped to fit the hole in the existing mount housing with the outer edges flared out. Then after it is collasped & inserted into that hole, a hollow center rod is inserted & secured in place by a snap ring. It can not come apart. The mounting bolt then goes thru the hollow rod just like the original.

 

[the machinist]

Re: 9.9/15hp top mount issues?

HM, I have to disagree that long shaft & short shaft upper mounts are different for either the 9.9 or 15hp motors as long as they are within the manufacturing years of 1974 to 1992. 1993 & newer are different (better design) but still the same for long/short shafts.

 

[Haffiman]

Re: 9.9/15hp top mount issues?

Was a change in #13 and #15 was changed. #13 got thicker to better take the thrust, relieving the thrust from #9. This first came on the Sail versions and Long shaft. Changing #9 without having the latest version of #13 and #15 will soon ruin the side mounts again.

 

[slowleak]

Re: 9.9/15hp top mount issues?

SL, if you had looked at may Powerhead/Midsection article that KB was referring to & looked at the illustration how I secured the rubber grommet, you would notice that there was no glue used, just the grommet center shaped to fit the hole in the existing mount housing with the outer edges flared out. Then after it is collasped & inserted into that hole, a hollow center rod is inserted & secured in place by a snap ring. It can not come apart. The mounting bolt then goes thru the hollow rod just like the original.

I guess I'm really not clear on the whole set up then, what holds the rubber in the hole?
The way I understand it the C clip is on the hollow tube through the middle? What keeps the whole thing from pulling through the mount bracket?

 

[reelfishin]

Re: 9.9/15hp top mount issues?

On the last two I had here that needed top mounts I just removed all the remains of the original rubber mount and took the aluminum bracket down to the auto parts store here. I was able to match up a front suspension bushing that would work. I think they were from an old Chrysler, the bushings had a lip on the rear side and were encased in steel. I just cut the whole bushing assembly roughly in half and pressed them in place. There's no way they will ever fall out and the solid rubber is far more durable than what was in there originally.
The bushings I found matched OD and ID but were a slight bit longer than needed but it made no difference. The bushings were pushed in from the rear side of each bushing bracket.
I'm not sure what the bushings were originally intended for other than they were in a misc bin of odd bushings at the parts store marked Chrysler. I suppose they're most likely either control arm bushings or similar. The steel will most likely one day corrode, but they did appear to be galvanized or coated in some way. I painted each complete assembly with self etching primer and a good coat of black epoxy paint before reinstalling them to help protect them.

 

[the machinist]

Re: 9.9/15hp top mount issues?

On my version, you grind a Vee groove in the outer diameter. With the hole in the middle it is like a doughnut. Collapse the center & you can work the whole outer ring into the hole of the metal mount. When you put the hollow bushing that accepts the bolt, in the grommet hole, that locks the grommet in place.

 

[the machinist]

Re: 9.9/15hp top mount issues?

HM, I bow to your knowledge, obviouisly I did not do any parts refference research, & spoke out of turn. As many of my observations are just by the seat of my pants repairs of what I see.

 

[Haffiman]

Re: 9.9/15hp top mount issues?

HM, I bow to your knowledge, obviouisly I did not do any parts refference research, & spoke out of turn. As many of my observations are just by the seat of my pants repairs of what I see.

Sorry I did not put a reference link into the post, I forgot:
http://www.marineengine.com/parts/j...manufacturer=Evinrude&section=Exhaust+Housing

However: #13 is there to take the thrust, #9 for the sideways vibrations. If (when) 13 fails or #15 gets 'bent' the thrust gets transferred to #9 which will ruin them in very short time. The 'new' #13 is thicker, the old #15 is a flat alu piece where as the new is a profile SST if remembering right. Changing #9 without getting the latest version of #15 and #13 is a waste of time and money.

 

[CatTwentyTwo]

Re: 9.9/15hp top mount issues?

I have a 1984 9.9 that I purchased new and it still has the original mounts. What do you look for and how can you tell when they need to be replaced?