95 Speedster Oil Pump Leaks?

[Ed355]

Hey all, first time posting. I bought a 95 speedster this past October as a winter project. It was half taken apart but mostly all there.
My motors were both full of oil when I bought it. I did a lot of research on this problem, and I've tested both the crankshaft seals on both engines for leaks. They both held 5psi for 15min no problem.
What I did notice is that the oil pumps (I assume that's what they are, the part that bolts between the carbs and block where the oil is injected) leak out of the injection ports when they're sitting.
I had them both disconnected from the engines and sitting next to them but still connected to the oil reservoir, and oil would drip out of the oil injection nozzles overnight. The engines when left connected to the oil supply did not fill up.
From my research this doesn't seem to be a common problem, as it seems to always be the crank seals or rotary valve seals. But those test fine.
Is there supposed to be a check valve or something to stop oil from constantly dripping unto the engine? My other thought was that since both throttle cables were disconnected when I bought it, the oil pump thought that the motor was under throttle and was allowing oil to flow. Is that possible?
Sorry for the long-winded first post, but I wanted to let you know that I've done my research on this and am stumped. Any thoughts? Thanks!

 

[Sportster-2001-951C-Stock]

Yes, check valves in the carburetor injection nozzles are likely stuck open. Good job troubleshooting, this has been a problem reported numerous times.

Nice to hear your crank seals are reasonably tight!

IMPORTANT BTW: You should think twice about attempting to remove the oil injection nozzles from the carburetors for cleaning, they're likely to snap off. You should be able to clean them if they're not too badly corroded just dirty, by using carburetor aerosol cleaner (this is acetone in pressurized can) or some other solvent and compressed air. Those check valves need to seal and keep the oil from dripping down the carburetor throats.

 

[Ed355]

Thanks! I will clean them then test them, do you know how they actuate? Are they one way valves or are they just designed to only open under pressure from the oil pump?

Yes, check valves in the carburetor injection nozzles are likely stuck open. Good job troubleshooting, this has been a problem reported numerous times.

Nice to hear your crank seals are reasonably tight!

IMPORTANT BTW: You should think twice about attempting to remove the oil injection nozzles from the carburetors for cleaning, they're likely to snap off. You should be able to clean them if they're not too badly corroded just dirty, by using carburetor aerosol cleaner (this is acetone in pressurized can) or some other solvent and compressed air. Those check valves need to seal and keep the oil from dripping down the carburetor throats.

 

[Sportster-2001-951C-Stock]

Oops, just realized I kinda made a little mistake that maybe confuses you, the oil injection nozzles are mounted in the carburetor base plate but they're similar to the accelerator pump injection nozzles mounted in later carb throats.

So yes, these are spring-loaded check ball type valves and engine vacuum actuates the oil injection nozzles open. Carb cleaner and compressed air should loosen and clean the gunk out of them, make sure they seal in one direction and you should be good to go.

The oil pump doesn't produce much pressure to push them open so if one nozzle is clogged that cylinder will of course starve of oil.

Also replace the rubber oil injection tubing, 3/32" ID Tygon F-4040-A is the type and size for that small tubing, they rot and crack sometime after about 10 or so years.

 

[Ed355]

I will clean and check them. Thanks so much for your help!

 

[Sportster-2001-951C-Stock]

Sounds good. One more thing I forgot to point out is if you're concerned the oil injection system isn't operating (maybe air bubbles or the oil pump adjustment isn't confirmed) you can at least initially run pre-mix in the fuel tank while testing for oil injection flow. The extra oil won't hurt anything necessarily but can cause plugs to oil-foul faster of course.

Aside FWIW: The injection system is the way to go b/c you'll save $$ on operating expense and it's reliable when maintained correctly. Just take the time to set it up and check it out, confirm it's working, purge out air bubbles etc. and either replace or reverse flush (replacement seems to be the preference) clean the in-line oil strainer filter feeding the oil pump if it's gummed up (maybe from previous mixing incompatible oil types?).

Accidental mixing of the correct type XPS 2T oil and outboard TCW3 oil in the oil tank leads to congealed goop clogging the oil injection system (esp. the oil strainer filter element), b/c these two oils have differing detergent packages which are incompatible thus shouldn't be mixed. When mixed, tends to become a gelatinous goop thus clogging up the works.

Great little motors and still rather cheap to replace as far as marine engines go. A compression check is in order frequently (~once/year) as a quick health check. Ideally you should see about 145psi on the 787 engines. Below 130psi is getting close to rebuild time. Comparable pressure between the two cylinders is what you want to see, seized rings can happen if run too lean of fuel (corroded carburetor) or lack of oil and this knocks the compression down quickly.

Maybe you know all this already, pretty common stuff to look for to avoid getting stuck on the ramp or worse in the middle of lake.

All the info you need is here on this site, and the 787 jet ski factory service manual is gold so get one if not already. Downloadable manual free in PDF format off the web.