Oil leaking from carbs, engine bogging down

[Yamahwilly]

New to this forum... I have read so many posts and can’t figure out what my issue is. I have a 1996 Yamaha S130TXRU that is experiencing an oil leak coming right out of the carbs after use. My motor is also bogging down as I go to throttle up and get on a plane, hard to restart after running for a bit (which I am starting to think is all a result of all this oil in the carbs... unless I just need to truly rebuild carbs - not worth it until I fix oil leak... but a sea foam mixture does make motor improve). After reading posts for days I want to say that my issue has something to do with check valves. My diagram shows in line check valves on the oil lines coming from the oil pump (oil pump diagram), as well as check valve assemblies right on the engine block where the carbs attach (air intake diagram). If anyone has suggestions as to which one of these is truly causing the issue/ how I can check the different valves to see if they are functioning that would be seriously appreciated. I haven’t been able to get back to the boat this week to check the onboard tank to see if it’s holding pressure (one thing I’ve read that I should check) but will do tomorrow. Again anything here helps.

[Jason2tpa]

Do you store the motor tilted up? If so, one or more of the check valves (#12) could be shot. Not sure how you could determine which check valve is bad, if any. Additional possibilities quoted below and pulled from a Yam Oil Inject troubleshooting document.....

Common symptoms of trouble include a lack of oil transfer, overfilling of the main tank, and oil leaks while the outboard is tilted. Most of the time, these problems are due to operator error and are not the components fault. While the outboard is tilted, a leaking rubber cap on the main tank can result from improper assembly or from twisting out of place. A plastic tie-wrap snugged around the rubber lip usually cures the leak. The clear sight tube on the bottom of the tank can become brittle with age, and oil may seep between it and the nipple. Replace the tube if it feels stiff, and secure it with a tie-wrap.


Regarding the bogging and hard start, I reckon this is fuel related and not oil related. Maybe time to pull carbs...If it’s been a while since you’ve pulled carbs to clean jets. If hard to start after long shut down period, have you tried squeezing primer a few times before cranking? This solves it every time with my motor.




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[brian3006]

It sounds like it might be time to pull the carbs and clean them. The bogging sounds like classic clogged main jet or float level.

As for the oil..arent the oil lines behind the carbs? when you say oil leaks from the carbs, I assume you mean oil runs out of the throat? (after being tilted) because otherwise there should be no oil in the carb. If so, then I would check your inline check valves. nothing to them but for some reason they are about $20 a piece. Each cylinder has its own line and valve. When you pull the carbs, run the engine briefly before you remove them. then when you remove them, see which one is dripping oil over the next few hours. follow that line back and check/replace the valve.
I had to replace one this winter. on my #1 cylinder, after sitting for a day, you could see an air bubble form in the line right where the oil line went into the intake. replaced the check valve and problem solved.

Just an FYI: if you do end up taking any of the oil lines off to test or replace a valve. make sure you run the engine on some 50:1 premix until the oil pump can pump oil back through that line. Otherwise no oil will be getting to that one cylinder.. 5-10 minutes at idle should be fine.