oil problem on yamaha 175

[fshlbi]

I have a 1993 Grady White Escape that I purchased last spring. I used this summer and put maybe 20 hours on it. Boat runs great. I have had two separate days, however, where I had a considerable oil leak.

I noticed the first leak when I got to the boat slip and saw there was oil draining out of the cowling and down the shaft. The motor was stored tilted so when I lowered it, the oil seemed to pour out of the manifold cover and into the bottom of the engine compartment. I thought that the drain hose on the bottom might have come unconnected, so I took off the manifold cover and tightened this hose.

I thought I was through with this, but later in the summer, a similar thing happened when I was running the boat and needed to tilt the engine slightly due to shallow water. I turned the engine off once I saw there was very shallow water and tilted it fully in order to drift across the bar. Again, there was a considerable amount of oil that dumped into the splash well.

I took it to a yamaha trained tech and he replaced the oil pump. I picked it up after that service and saw oil in the bottom of the engine again, so I did not even run the boat, just dropped it back off. They insist there is no leak.

I only ran the engine one more time since then and that was in order to fog the engine. I am not sure that the leak is fixed. When I fogged the engine, I did see what looked like oil pouring out of the carb intakes. I could not tell if it was from the fogging oil or if it was engine oil.

I also noticed that there is a tilt/sensor/sending unit in the engine oil reservior. I am wondering if this unit could have gone bad. It seems to match the symptoms more than the oil pump.

Has anyone else had this problem?

 

[enfish]

FWIW, a lot of people have problems with the cap leaking on the oil tank under the cowling. We put a zip-tie around the cap to stop the leaking when the motor is tilted up for storage. It's not perfect, but we only get an ounce or two of oil that drips out over a few months.

 

[fshlbi]

it seems to be coming more from the carburetors. It is leaking out of the cover that it is in front of the carbs. Almost like the pump is over filling everything. That's why I was wondering whether it could be that sending unit/sensor that is in the reservoir. It seems like there is a float switch that might talk to the oil pump. There already is a zip tie over that cap. It's definitely not coming from there.

 

[seasick]

I have a 1993 Grady White Escape that I purchased last spring. I used this summer and put maybe 20 hours on it. Boat runs great. I have had two separate days, however, where I had a considerable oil leak.

I noticed the first leak when I got to the boat slip and saw there was oil draining out of the cowling and down the shaft. The motor was stored tilted so when I lowered it, the oil seemed to pour out of the manifold cover and into the bottom of the engine compartment. I thought that the drain hose on the bottom might have come unconnected, so I took off the manifold cover and tightened this hose.

I thought I was through with this, but later in the summer, a similar thing happened when I was running the boat and needed to tilt the engine slightly due to shallow water. I turned the engine off once I saw there was very shallow water and tilted it fully in order to drift across the bar. Again, there was a considerable amount of oil that dumped into the splash well.

I took it to a yamaha trained tech and he replaced the oil pump. I picked it up after that service and saw oil in the bottom of the engine again, so I did not even run the boat, just dropped it back off. They insist there is no leak.

I only ran the engine one more time since then and that was in order to fog the engine. I am not sure that the leak is fixed. When I fogged the engine, I did see what looked like oil pouring out of the carb intakes. I could not tell if it was from the fogging oil or if it was engine oil.

I also noticed that there is a tilt/sensor/sending unit in the engine oil reservior. I am wondering if this unit could have gone bad. It seems to match the symptoms more than the oil pump.

Has anyone else had this problem?

What is the year and model of the motor?

 

[suzukidave]

are you sure it's oil and not mixed fuel? mixed fuel at the carbs has the colour of oil. fuel/oil is mixed at the pump so pure oil is pretty unlikely to come out of the carbs but a bad float will cause mixed gas to leak, especially when tilted, matching your symptoms.

 

[DennisG01]

To add to the above... as it collects, the gas will start to evaporate - thereby making it a thicker consistency again.

 

[seasick]

If your motor is 1988 vintage or there abouts, there is an oil pump. The output of the pump varies depending on the throttle position. There is linkage that connects the throttle to the pump lever. If the linkage is broken or mis adjusted, the oil pump will pump more oil than needed, especially at lower revs. So just to eliminate that possibility, check the 'Oil synchronization'.

 

[fshlbi]

These are all very helpful. I didn't think of the idea of it being mixed fuel. I just thought of it as oil, but it very well could have been a mix. As for the linkage, if the mechanic replaced the oil pump, I would think any linkage issues would have been noticed and addressed.

The motor is the same year as the boat. a 1993 Yamaha 2 stroke 175.

All ideas are appreciated...

Thanks for the suggestions.

 

[seasick]

These are all very helpful. I didn't think of the idea of it being mixed fuel. I just thought of it as oil, but it very well could have been a mix. As for the linkage, if the mechanic replaced the oil pump, I would think any linkage issues would have been noticed and addressed.

The motor is the same year as the boat. a 1993 Yamaha 2 stroke 175.

All ideas are appreciated...

Thanks for the suggestions.

It's easy to check. Look at the oil pump linkage and see if the lever tab is against or very close to the stop on the pump. It should be and then when the throttle is advanced, the lever should turn and the gap between the stop and the lever should get bigger. The pump lever is spring loaded and if the throttle lever is disconnected or has a broken clip (somewhat common) the spring will rotate the lever towards open ( max oil).

I do have another question; When and why was the pump replaced? If it was replaced before you noticed the oil, that would be a big clue as to the source of the oil

 

[fshlbi]

oil pump was replaced after i saw the leak. the mechanic checked consumption saw that it was high, and replaced the pump as a fix for the leak.

unfortunately, the end of season made me unable to really use and test, so i have no idea whether the leak is fixed.

 

[seasick]

oil pump was replaced after i saw the leak. the mechanic checked consumption saw that it was high, and replaced the pump as a fix for the leak.

unfortunately, the end of season made me unable to really use and test, so i have no idea whether the leak is fixed.

I am curious as to how the mechanic determined that the oil pump was at fault. The only accurate way to determine the oil flow rate is to measure the output ( by disconnecting the output hose) and pumping oil with the motor running into a measured container and timing how long it takes for a certain amount of oil. That is actually not too difficult BUT since the oil hose is disconnected, you have to run the motor on a supply of premixed gas and oil. That can be a pain to set up.
In any case, check the oil sync linkage. You should check it as part of the normal pre-season prep work.
Good luck

 

[Andrew93]

This is just an educated guess after fighting a different problem on the oil system on a 1994 150hp yamaha I had. Maybe the trim sensor switch is in the stuck down position, they usually get cruddy and stay down or break off. When the switch is down the oil system works normally, when it is up (when he motor is trimmed up) and the oil level drains in the main oil tank (the one under the hood) it calls to be filled by the remote tank (the big one you add to). If the switch is always down even when you trim the motor up and the oil level in the main tank is low it may call to be filled but because of the angle of the motor the float switch is never triggered off causing it to overfill and make a mess.

Something worth looking at and an easy fix, it would also explain why it does not do it all of the time.

good luck

Andrew

 

[seasick]

This is just an educated guess after fighting a different problem on the oil system on a 1994 150hp yamaha I had. Maybe the trim sensor switch is in the stuck down position, they usually get cruddy and stay down or break off. When the switch is down the oil system works normally, when it is up (when he motor is trimmed up) and the oil level drains in the main oil tank (the one under the hood) it calls to be filled by the remote tank (the big one you add to). If the switch is always down even when you trim the motor up and the oil level in the main tank is low it may call to be filled but because of the angle of the motor the float switch is never triggered off causing it to overfill and make a mess.

Something worth looking at and an easy fix, it would also explain why it does not do it all of the time.

good luck

Andrew

The Precision Oil system no longer uses the trim sensor as part of its logic. That change was mad a while back but I am not sure which year. By the late 90s for sure, the trim sensor is not used.
Of couse if the system pumps more oil into the main tank than it can hold, it will leak but it will leak into the cowling housing. That oil tends to pool on the bottom of the cowling and leaks when the motor is tilted down. The oil does not flow into the intakes or the VST for injected motors.
Also note that on older motors that use the trim sensor, the oil can only pump when the ignition is on, so just tilting up the motor with the batteries off will not cause oil to overflow.
I guess I've beat this topic to death.
Hopefully your system works fine next season.

 

[fshlbi]

Okay, I really appreciate the replies to this. A lot of good information. I am worried about the possibile replies to this latest update, but here it goes....

I recently went down to remove the batteries for the winter, so I can have boat shrinkwrapped to protect it. I noticed that there is a small indication on the driveway under the engine (i stored it tilted down) that the engine is leaking oil into the cowling even when just sitting in the driveway.

Appears to be collecting in the cowling area and then dripping slowly down the shaft down to the driveway. Again, not sure if just oil or mixed fuel and oil, but I am assuming that this is not a good sign? I did have the mechanic check the compression on the engine and it was within the proper running limits. however, I'm thinking this is really not a good sign. what would cause it to leak when just sitting in the driveway?

my thoughts are going to cracked block, but the part that confuses me is that with it being a two stroke, there shouldn't really be collected oil in the engine other than the reservoir tank inside the engine.

thoughts?

 

[suzukidave]

Okay, I really appreciate the replies to this. A lot of good information. I am worried about the possibile replies to this latest update, but here it goes....

I recently went down to remove the batteries for the winter, so I can have boat shrinkwrapped to protect it. I noticed that there is a small indication on the driveway under the engine (i stored it tilted down) that the engine is leaking oil into the cowling even when just sitting in the driveway.

Appears to be collecting in the cowling area and then dripping slowly down the shaft down to the driveway. Again, not sure if just oil or mixed fuel and oil, but I am assuming that this is not a good sign? I did have the mechanic check the compression on the engine and it was within the proper running limits. however, I'm thinking this is really not a good sign. what would cause it to leak when just sitting in the driveway?

my thoughts are going to cracked block, but the part that confuses me is that with it being a two stroke, there shouldn't really be collected oil in the engine other than the reservoir tank inside the engine.

thoughts?

gravity. any liquid above the leak will flow through.

if it's a a stuck carb float or a leaky carb bowl drain plug that will drain all the fuel in the fuel line above the carb float and maybe empty the bowl too. that would be enough to make it to your driveway.

also, in some engines a stuck float will allow fuel to drain into the engine which can then leak out the exhaust

 

[seasick]

Okay, I really appreciate the replies to this. A lot of good information. I am worried about the possibile replies to this latest update, but here it goes....

I recently went down to remove the batteries for the winter, so I can have boat shrinkwrapped to protect it. I noticed that there is a small indication on the driveway under the engine (i stored it tilted down) that the engine is leaking oil into the cowling even when just sitting in the driveway.

Appears to be collecting in the cowling area and then dripping slowly down the shaft down to the driveway. Again, not sure if just oil or mixed fuel and oil, but I am assuming that this is not a good sign? I did have the mechanic check the compression on the engine and it was within the proper running limits. however, I'm thinking this is really not a good sign. what would cause it to leak when just sitting in the driveway?

my thoughts are going to cracked block, but the part that confuses me is that with it being a two stroke, there shouldn't really be collected oil in the engine other than the reservoir tank inside the engine.

thoughts?

You worry too much. It is a 2 stroke, there is no oil in the block to leak. If the block were cracked, you would know it and not by seeing oil drip.
The oil dripping off of the lower unit from the cowling is a classic sign of the oil tank overflowing/leaking when the motor is tilted up. The oil pools in the bottom of the cowling and them when the motor is lowered, it finds a way out.
If oil continues to leak out with the motor down as when stored, you need to look for a leak in the oil plumbing. Resist the temptation to turn on the battery switch and or ignition. Monitor the oil level in the main tank (on the motor) to see if it is going down. If you turn on the ignition, the tank will refill. There is a relay that gets engaged when the ignition is on and that controls a lot of things. If the relay is stuck on, everything in the motor gets powered up when you turn on the battery switch. That is why I said to resist that temptation.

 

[lime4x4]

Had the same problem on my 88 150 yamaha's. Found the lower bottom bolts were missing on the carb baffle causing the gasket not to seal. So when i tilted the engine up same gas/oil would drain out of the carbs then when i tilted the engines back down instant oil leak