Question for Rodbolt/Boscoe

[SeaDawg3]

what is this red sealant between the cases in this photo? does not look like yamabond or 1211. feels like grease.
and what can you surmise just from the photo?
yes there are wrench marks on the exhaust cover and almost all the bolts found, except the shiny lower/upper case bolts.

found hoses out of place, hoses have been shortened/cut for a new end, those wire clamps have been touched, quite a few zip ties cut and laying in the bottom of the cowl/pan.
and a zip tie around the plastic joint for the oil pump.

I hear it is common for those plastic joints to crack.
was easy getting a replacement, wondering why the tech who worked on this 90 just didn`t replace the plastic joint... hmmm

anyway, what are your thoughts?

[99yam40]

I am not one of those you were looking for, but what makes you think it was a tech that did all of that?

[SeaDawg3]

I am not one of those you were looking for, but what makes you think it was a tech that did all of that?

where did I ask that? Oh I see bc I was respectful and called the person a tech.

I figured rod/bos would be the first to recognize and reply.

I have no clue who did what, but do know it was a one owner engine, and the owner did not wrench. Some shop in NC did work on it.

My forte` is not outboards, but I can tell this has been apart. maybe for the good, and maybe to hide the bad... don`t know.

the certified yamaha tech I hired to do the inspection and sea trial said it was good to go, and the 90 is a great engine. I did not discover this until the boat was in my driveway.

she runs good though.

someone in the know who could tell me what should be at the case joint would sort of prove the bottom end has been apart. whatever it is, it is pretty fresh and bright. not washed out or sagging as if it were there for the duration of 13 years. but I could be wrong.

[99yam40]

ACC-LCTE5-18-31 LOCTITE GASKET MAKER
This should be the gasket maker that is used to put the case back together, you should look at your service manual to be sure

From what I have seen it does not get hard

[SeaDawg3]

thanks 99yam.

I have the Seloc SM. So far I have seen the use of yamabond 4.

Is the product you attached a 518, like the anerobic?
edit: yes it is 51831, a red gel anerobic flange sealant.

Ok I have that, and it is a gel substance, not like the uncured stuff I have on the case.

I use the 518 to seal jet pump cones and venturi`s and know the feel of that when cured and when not.

the next question is, what would have been used back in 02 on a new production powerhead?

being this is 2015 I could see the loctite being used from a shop.


now we are getting somewhere...

[boscoe99]

The red goop, wrench marks on a number of fasteners and the other stuff you describe would leave me to believe that the motor has been opened up and then reassembled.

I can't remember the name of the stuff I have used but one of the sealants was gel like and red colored. Anaerobic means it cures in the absence of oxygen. So, the stuff between the mating surfaces should have cured. The stuff on the outside will not cure because it is exposed to the oxygen in the air.

Tech (short for technician) is the high falutin politically correct word of the day for mechanic. Next they will want to be referred to as engineers.

[SeaDawg3]

The red goop, wrench marks on a number of fasteners and the other stuff you describe would leave me to believe that the motor has been opened up and then reassembled.

I can't remember the name of the stuff I have used but one of the sealants was gel like and red colored. Anaerobic means it cures in the absence of oxygen. So, the stuff between the mating surfaces should have cured. The stuff on the outside will not cure because it is exposed to the oxygen in the air.

Tech (short for technician) is the high falutin politically correct word of the day for mechanic. Next they will want to be referred to as engineers.

Yup lots of fancy titles today. Just look at the job boards.
I've earned my journeyman status. Thankfully it is not politically attached.

So my suspicion is valid. Why or what needed attention is up to the imagination. Dam dam dam...

Well I'll run it until she runs no more. All I can do.
Even the lower unit was removed at some point, hopefully someone was smart enough to install new seals and a WP kit. But not likely for the prop shaft external seal by the looks of it.

Well whatever was done by the tell tale signs, someone got a good sized bill.
And I'm sure I covered some of that in purchasing the boat. Ouch.

[zenoahphobic]

Anaerobic sealant should be used sparingly so minimal is left outside of the airtight joint staying sticky.

[Bus pants]

A friends C90 has that red sealant too. It does seem very grease-like. I wondered the same thing as you.

[rodbolt17]

that red stuff was used for years by Yamaha.
wire tie chunks in the cowl means some one was sloppy.
a wire tie around the oil link means some one was cheap.

[99yam40]

This got me thinking , I wonder if Yamaha would have a record of the motor and what all has been done to it by a Yamaha shop.
Not likely but maybe
What problems would need the case split
Pistons, crank, seals, sucked in broken reeds, ???

[boscoe99]

This got me thinking , I wonder if Yamaha would have a record of the motor and what all has been done to it by a Yamaha shop.
Not likely but maybe
What problems would need the case split
Pistons, crank, seals, sucked in broken reeds, ???

Yamaha's records only relate to work done under warranty, or as goodwill which was paid for by Yamaha. Any other work is not recorded in Yams system. Yam USA that is.

The OP can certainly call Yamaha and see what is on file with respect to his particular motor. If it is a USA model that is.

[SeaDawg3]

Thanks fella`s. see what happens when the mind wanders.

I could think about it`s past life for decades and still come up short as to the history of this one.
If the engine sat for years, it would look this clean, and yet maybe have a failure from sitting to long, rust, bearings, seals, fuel etc etc.
but no barn dust, no bugs nest or critters.

if the engine were used, surely it would be more "dirty", more salt build up under the cowl. there is no evidence of this engine being washed down.
There is evidence that areas have been painted, and painted poorly over the corrosion.

the bottom case half, the intake/reed assy. and the carbs exterior are spotless.
there was a hint of your normal salt water residue around the gasket`s edges on the exhaust cover, head etc. other small plastic covers and some hidden spots are covered in mold. same as many hidden areas of the boat itself, but we are talking about a boat here so that is to be expected.

the shine you see is a light spray of CRC56.

when I replaced the fuel filter assembly with new, I could easily open the old one. It did not give me a fight like most posts I`ve read said.

so I can guess that service work had been done, or worse case >, a major repair from a failure and then the boat was put up for sale...

maybe the PO diligently took care of this engine as needed or scheduled services.

If I had any complaint per say, the engine is loud when cruising along, decibel wise...


Rod, thanks for confirming the "red" sealant.
when I was first inspecting what I bought, my first impression was ***, new sealant, shiny new bottom end bolts, and a very clean lower case half, hmmm what happened here...

but I guess I`ll never really know for sure...

[SeaDawg3]

Anaerobic sealant should be used sparingly so minimal is left outside of the airtight joint staying sticky.

agreed, I generally use enough to do the job with minimal squeeze out, and given the application I`d probably wipe off the excess.

also leaves to the imagination why Yamaha didn`t use yamabond or 1211.

[99yam40]

Yamaha's records only relate to work done under warranty, or as goodwill which was paid for by Yamaha. Any other work is not recorded in Yams system. Yam USA that is.

The OP can certainly call Yamaha and see what is on file with respect to his particular motor. If it is a USA model that is.

There you go, if it was under warranty they should have records of what was done. Cross you fingers and make the call


As you said a motor that sits can have problems with rust on shiny internal parts.
I had 3 of the main bearings on my C40 that were rough when rolled by hand and saw a small spot of rust on the crank when I pulled it apart. being the 2nd or 3rd owner means you have no idea what has happend to the motor .