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Pulling 2003 5.7 350 - What should I change inspect ?

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abl1111

Regular Contributor
I'm having my 2003, 5.7 - 350 MAG MPI with 850 hours pulled to replace the Bravo transom mount assembly ( inner/outer, gimbal ring, housing etc ).

While the engine is out, what should I have checked or replaced ? Anything I should just 'do' while I'm there ?

Thanks.
 
to check:
starter,oil pan, bilge pump and its wiring, Y pipe for corrosion, clean and paint bilge, clean/replace front mounts and rear mounts,
lube steering tube guide to name a few
 
Last edited:
If used in sea water and if raw water cooled: inspect/replace exhaust manifolds and elbows.
If "fresh" water cooled: inspect/replace elbows. Check raw water side of heat exchanger.
 
need more info on motor.........how many hours and such..........etc...etc....etc....


If high hours may be a good time to change the timing chain.........maybe valve job, maybe coil????


Tell us more of what the motor has been thru...
 
Thx for all the input. I've taken notes. The engine has been taken care of very well ( aside from the fact that I didn't know that the gimbal ring nuts needed to be torqued every year and my gimbal ring took a shee'at ). She has about 850 hours and is run at 3200 rpm's for about 90% of her life - the balance is idle and every so often full throttle. The engine looks and runs mint.

I replaced the:

elbows and gaskets ( elbows were shot at 600-650 hours )
heat exchanger
fuel pump
water pump

I want to have exhaust shutters replaced. I have original ignition wires and plugs. Cap/rotor is 3-5 years old. Throttle/shift cables also original.
 
He is referring to the PINCH bolts on the gimbal ring/steering pin location.....He never tightened them as his ring was wearing to the steering pin. Of course we know that it is a limited adjustment due to the bolts being a shoulder bolt. But he or anyone prior to him never checked that area. This was his original issue posted in an earlier post.

He said he is going to a bravo set up, The Bravo uses a U bolt but the same applies. It needs to be checked and tightened if need be. But it can only be tightened so much and then the G ring to steering pin issue can happen all over again. But if kept tight it can last 20 - 30 years with no issues.

At 850 hours regardless of the rpm's you run it at you are reaching a point where internals can wear down/out.

If you are happy with the overall motor then just leave it. But beware that in another 500 hours you may require mechanical work. such as valve job, timing chain.... Maybe, maybe not. but just be aware....they don't last for ever..........

I would replace the coupler anyway...good catch Chris. It is a wear part and should be done NOW while the motor is out of the boat. Then good for another 1000 hrs if aligned properly.

If your ignition parts are 3-5 years old, I would definitely replace the plugs, cap, and if the pick up sensor is not the one that is completely encapsulated and is the old style with the circuits exposed I would replace that also. Keep the old one for a spare. Not a bad idea to replace the coil...cheap enough and keep the old as a spare.
 
Thx again. Motor seems to be fine for now. It has a Bravo 3 now and I'm replacing the entire transom bracket etc as opposed to just the gimbal ring. Not knowing those 'pinch'-nuts needed to be torqued cost me a lot of $ !!! I have never read in the mercruiser shop manual, under maintenance, that these should be checked. I know now !!!! BTW - what is the torque for these for the future ?
 
here is the spec....

this is new...as the steering pin to gimbal ring wears that may or may not be enough...but you can only tighten so much.....not enough threads....you will see...when you either look at the old U bolt or new one.
 
abl1111 said:
Thx again. Motor seems to be fine for now. It has a Bravo 3 now and I'm replacing the entire transom bracket etc as opposed to just the gimbal ring. Not knowing those 'pinch'-nuts needed to be torqued cost me a lot of $ !!! I have never read in the mercruiser shop manual, under maintenance, that these should be checked. I know now !!!! BTW - what is the torque for these for the future ?
Click to expand...

The only time these nut should be re-torqued is at initial install of the transom assembly, the next season they should be checked and that is pretty much it.

Unless your pinch clamp was extremely lose, I doubt that is the reason your ring was worn.

Is your boat docked in shallow water? Do you water ski or pull a tube with the boat?

Worn gimbals can be repaired with out pulling the engine and transom assembly.

FYI....I would get the Seacore Assembly if installing a new one..
 
I remember the drive having play from the first 3-4 years. The mercruiser mechanic just said, " thats a mercruiser ". I will check the torque each year from now on - live and learn.

No tubes, skiers act - I've wondered if the gimbal ring is loose from hitting shallow sandbars over the years. It does happen around here - within a season, the sandbars shift, the tide/moon creates lower tides than normal, or the 'big nut' at the wheel just blows the channel. Sometimes it can be a light tap through sand and other times it can be more.

I opted not for the SeaCore - I asked a couple local mechanics and they said get the standard stuff. I bought it online so they had no bias. And, I thought about just doing the ring, but the shaft gasket is shot too and I was told by the time I replace all the parts, and the ones I donut know I needed, I'd be pretty close to the cost of the whole assembly.

Pulling her today - it's 40 degrees here on LI. I wish it was warmer so I could clean, spray the bilge when the engine is out.
 
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