coolant leak from side panel of engine.

[VonGustaf]

Hi. I just bought a Royal Venture - 89 and have a problem with a coolant leak.

it comes from a hole in front engine half from under the side panel that sits on engine half..

What is this hole and why can it leak as that??

 

Thanks in advance... /Kent

[Prairiehammer]

It is a water jacket drain hole and should have a rubber plug in it.

http://www.boats.net/parts/detail/yamaha/Y-90338-11152-00.html

[bongobobny]

Yup! And probably a very good idea to clean/ream/drill out the hole before installing the new rubber plug if you don't want the new one to leak even worse. Just don't make the hole any bigger than what it already is, within reason, or the new plug will not fit properly...

[VonGustaf]

Thanks for reply. Strange that i have ride at least 700km and not have any leak before as it have not been any plug in hole....

[bongobobny]

Might be a big "clot" of rust, sludge, and crud that is acting as a plug...

[cimmer]

I would suggest check the other plugs to make sure they are there also just in case you need to order all 4. These are fairly easy to access. The easiest way I have found to pull them out is with the terminal end of a spark plug. Remove the cap to wear you just have the treaded end of the spark plug and it will screw into the plugs in the cylinder jacks and then give it a pull and out comes the plug. Just remember there is coolant behind the plug.

Good luck.

Rick F.

[Black wing]

the hole the arrow is pointing to is the water drain for around the spark plug. it lets water escape so it doesn't pool around the plug. all the oils and dirt that fall in there get flushed out with the rain water.

Edited September 8, 2016 by Black wing

[yamagrl]

This the plug that everyone above is referring to. Those covers put force on those plugs to hold them in place. Do not run the engine with those covers off. The plugs will be blown out as the cooling system heats up and builds pressure.

 

[bongobobny]

Yup!!!!

 

I just ASS-U-ME'd that he took the cover off to show where the leak was coming from. Figured he saw weeping coming from the cover and investigated...

[yamagrl]

Yup!!!!

 

I just ASS-U-ME'd that he took the cover off to show where the leak was coming from. Figured he saw weeping coming from the cover and investigated...

 

You're probly right but better safe than sorry.

[VonGustaf]

Yes i saw it pouring down engine case and down on floor. Took cover of and started the engine. after ca 30-40 sec it started to pour out of hole and it is coolant fluid as it is green. if it is the sparkplug drain hole then i think i have a leak somewhere else.... :/

[Black wing]

if that is the rear right cylinder its coming from the hose at the top of the head and running down into the spark plug relief.

[yamagrl]

if that is the rear right cylinder its coming from the hose at the top of the head and running down into the spark plug relief.

Or the left front