question on rebuilding a 150 hpdi

[gruff511]

Hey guys to keep it short; i recently got a 2004 150 hpdi motor from my father. It was rebuilt in 2012(not sure what was replaced) and then was only used for less then 100hours in saltwater. It ran like new never had a problem then the boat sat for the past 3 years and was never started or flushed out. All the old oil gas and oil and salt water was never flushed out.
So im currently going to rebuild the whole motor. I ordered a seloc repair manual hoping that will help me out a little. And i seen on the yamaha parts website they offer all the replacement parts also.

Now my question is, how do i read engine performance and check codes? I know you can connect these efi engines to a computer to check codes and performance, is there anyway i can do that? Or does only a yamaha mechanic have access to that?
Any help is appreciated, thanks!

[robert graham]

Just because it sat for 3 years wouldn't necessarily require a complete rebuild....how about a fuel system clean/flush, oil change, foot oil change...then run the motor and see what you've got?....it may surprise you how well it does!...

[gruff511]

Thanks for the reply. I was just thinking of doing a complete rebuild because a couple buddies of mine who work in the marine industry said im going to have to go through the whole motor, plus i want to be sure the motor is reliable im not a fan of anything failing out on the water

[ausnoelm]

OK, first thing, toss the Seloc manual away and buy a genuine Yamaha one if you are thinking of a rebuild, also agree that just because some buddies said it will need a rebuild, doesn't mean it does, providing it was going OK before it "sat", do the basics, get it going and see what it has.

[boscoe99]

I second or third the position that the motor does not need to be rebuilt.

The oil does not wear out. Oil (about 99.999% percent anyway) in this model does not mix with gasoline. The internals of the motor that get oil should be just fine.

Some never ever flush their saltwater motors and never have a problem with the cooling system.

The gasoline may or may not be a problem. I would purge the fuel system of the old fuel, add new fuel and see how she lights up and runs.

Oh, the impeller might or might not need a bit of attention. And, it would not hurt and is not expensive to change the lower unit oil.

[robert graham]

Thanks for the reply. I was just thinking of doing a complete rebuild because a couple buddies of mine who work in the marine industry said im going to have to go through the whole motor, plus i want to be sure the motor is reliable im not a fan of anything failing out on the water

When your buddies said "go through the whole motor" they probably/hopefully meant to clean and flush the fuel system, change oil, check water pump, etc., then go run the motor...a complete motor rebuild is a lot of expense and time...

[ausnoelm]

And just to add (again) toss the Seloc manual and get a genuine one, it will be well worth it very soon.

[gruff511]

Where can i get a genuine yamaha manual? Any places online?
Ok im going to start doing some work on it this week i drained the lower unit oil it was ****en and clear but some milky oil came out also, which seal would that be thats leaking water into to oil?

[99yam40]

You pressure test lower unit like the service manual calls for to see what needs replacing.
There are seals on drive shaft, prop shaft , shift shaft,o rings on the carrier, and gasket on the drain and level screws

I would be more leery of a motor failing after someone that does not know a lot about the motor opened it up and rebuilt it than just figuring out problems it has and fixing them if it has any.

You can get a Yamaha service manual for your motor from Yamaha

[gruff511]

Alright thanks ill get a yamaha manual. If i dont rebuild the motor i will still replace all the gaskets and seals in the motor and lower unit.

[rodbolt17]

I would disassemble NOTHING.
I would drain the gearcase and pressure test it.
I would drain the engine oil tank water trap.

I would clean the VST and replace the filters and drain the hull tank and start with fresh fuel
I would change the water pump as it has a set from sitting 3 yrs.

but that's just me.

[robert graham]

I would disassemble NOTHING.
I would drain the gearcase and pressure test it.
I would drain the engine oil tank water trap.

I would clean the VST and replace the filters and drain the hull tank and start with fresh fuel
I would change the water pump as it has a set from sitting 3 yrs.

but that's just me.

Amen on this!.....no need to just make a lot of trouble and expense for yourself...

[BQUICK]

Changing all the gaskets risks bolts snapping. I wouldn't risk it.

Knowing when to leave some mechanical thing alone can be as important as knowing how to work on it.

[gruff511]

Thanks guys im doin what rodbolt17 said im currently flushing all the old gas and oil out. Just going to replace the oil lines that are leaking a little. I inspected all the engine gaskets and all seem to look good.
I pressure tested the lower unit and and the prop shaft seal is leaking so i started tearing it apart to replace all those seals and while im in there ill replace the impeller and water pump seals.

[gruff511]

Alright im still cleaning up the motor but i have the lower unit removed and the lower unit is seized up, the drive shaft wont turn at all.
Is there an interchangeable lower unit that i can look for locally and use? The motor i have is the 2004 150 hpdi z150txrc so is there a different LU i might be able to look for to use?
Im still in the process of disassembling the lower unit, this bearing housing is seized inside as well.