2000 c90tlry missing pipe

[Mars1351]

I bought a boat that came with allegedly a 2000 yamaha c90tlry. 90hp 2 stroke. The previous owner by passed by the prime start by blocking the rear hose of the prime start and then connect the vacuum tubes with a selenoid choke. As im cleaning the carbs and reinstall, i notice the brass pipe from the crankcase is missing. Any idea why or if the engine is a different model.

[99yam40]

only way to know is ask the guy that did it.
maybe he did not know anything about a Yamaha prime start and used something from a different motor because he knew how that worked.

[DennisG01]

In your second picture, it doesn't appear to be missing. It looks to be plugged from the factory (silver paint) as if it's supposed to be that way.

But... more importantly, how does the engine start and run? Good? Move on and go boating.

[Mars1351]

From what i gathered. They removed the oil injection parts. They replaced the case that has the oil injection ports. Then the prime start gave out and they rigged like this. But the engine wont turn on unless u prime the air vent with ethanol spray. If anyone knows, i was thinking of drilling the hole out, adding the brass pipe. Yamaha sells the pipe for 7 dollars.

[Mars1351]

I cant find any yamaha engine that has the pipe missing and blocked. All the research ive done have some type of exit pipe thay supplies air pressure to the rear prime start. Every service manual and part catalog shows this pipe.

[boscoe99]

The parts catalog is not showing any sign of a hose to or from the PrimeStart device that I can see.

[boscoe99]

I do see a hose from the intake manifold to a port adjacent to the PS device.

[boscoe99]

only way to know is ask the guy that did it.
maybe he did not know anything about a Yamaha prime start and used something from a different motor because he knew how that worked.

Amen brother.

[boscoe99]

Very difficult to provide any meaningful information about a motor, the modifications to which are unknown to us.

[Mars1351]

So the hose the is highlighted is on my engine. As for the part catalog it dosent show it there but on the next part is shows is

[99yam40]

if they changed parts to get rid of the oil injection,
there is no telling what all they changed,
and there is no telling what all is wrong or modified


I am not sure if the 90 PS is the same as my C40, but here is a drawing I did on mine a few years ago, showing where each port went to.
there are 3 hoses the rest are drill passages

[robert graham]

Can’t figure why anyone would disconnect a very trouble-free enrichening system like a Primestart????