i all, my uncle passed away and left my family a Yamaha MS24 with what i believed was a Yanmar YSE8 engine.

Unfortunately, we could not get it started after bleeding the fuel line, so i removed the fuel injector pump and found the fuel plunger had broken.

Initially I had a tool maker fabricate a new plunger (using the dimension from the broken one ) however that did not work.

Not being able to find any parts in my country - Australia , i have decided to order an OEM pump from Taiwan, but when i checked the identified plate on the engine it is not a YSE8 but a YS8.

Are these the same engine ? or more importantly is the fuel injector pump interchangeable on these two models ?

According the build spec sheet (found on the internet) they were built with an YSM8, which is also referred to as just YS8.

I have attached some pics, any help would be much appreciated.

Also if anyone has had experience with ordering a OEM fuel pump from Taiwan and if they are reliable that would be great also.

My next challenge will be re-seting the governer throttle, as I have only found instructions as it relates to the YSE8.

Thanks in advance.

( i have photos but first timers can't post images - hopefully in time i can attach them )

Hi Gary, thank you for your responses.

I will go ahead and order the OEM part from Taiwan, fyi the current cost including delivery $420AUD.

This includes the fuel pump, spring, plunger pin, bolts etc.

Thank you for the Governor throttle instructions, I believe the instructions I found on the internet are the ones you had already posted - so thumbs up !!!

I have attached some pics, hopefully the admin will let me post them.

Giving this a little more thought.
I think you should try to check for any internal damage.
A simple check is to remove the oil filter (a triangular flange with a T handle sticking out) from the front housing.
Scoop out any oil inside into a clean dish.
Stuck a magnet in to check for steel or iron debris and run the oil between your fingers to feel for any other stuff.
I have done this with two YS engines and found nothing.

gary

New non genuine fuel pump arrived today, and i noticed the pin stamp is missing on the top of the throttle pin. ( picture attached)

I guess i will just seat the throttle pin, remember the location of the screw head and CCW 90 degrees for the correct setting ?

Will also change out the oil and clean the oil filter, i already have some Shell HX5 15/40 (new) on the boat, or should i go with something else ?



Taiwan - Sunity YS8 replacement fuel pump



Replaced the original fuel filter, with a new filter and bleeder screw and new fuel hoses, with a pump to assist with bleeding.