Gold Member Kivalo Posted September 3, 2023 Gold Member Share Posted September 3, 2023 Installed in a Chaparral Sunesta 243 Deckboat. The gear oil reservoir goes from the full line to the fill line in about 20 miles. No visible leaks around the outdrive, no oily mess in the engine bay or bilge. Any ideas on where this oil is going?? Quote Link to comment Share on other sites More sharing options...
Deephaven Posted September 3, 2023 Share Posted September 3, 2023 Gear oil? Thought that boat was an IO and had trim and outdrive fluid but just a bit of lube on a splined shaft. Quote Link to comment Share on other sites More sharing options...
Voodoo Posted September 3, 2023 Share Posted September 3, 2023 Really can only go out the tail, or if it's a remote reservoir it may be leaking in the pipe from there to the case. Pressure test it. Quote Link to comment Share on other sites More sharing options...
Not greg b Posted September 3, 2023 Share Posted September 3, 2023 35 minutes ago, Kivalo said: Installed in a Chaparral Sunesta 243 Deckboat. The gear oil reservoir goes from the full line to the fill line in about 20 miles. No visible leaks around the outdrive, no oily mess in the engine bay or bilge. Any ideas on where this oil is going?? Pump the drive up and see if it holds pressure. If it doesn’t it needs to be taken apart and re sealed Quote Link to comment Share on other sites More sharing options...
Gold Member Kivalo Posted September 3, 2023 Author Gold Member Share Posted September 3, 2023 2 minutes ago, Not greg b said: Pump the drive up and see if it holds pressure. If it doesn’t it needs to be taken apart and re sealed What do you mean "pump the drive up" ? Quote Link to comment Share on other sites More sharing options...
Gold Member Kivalo Posted September 3, 2023 Author Gold Member Share Posted September 3, 2023 1 hour ago, Deephaven said: Gear oil? Thought that boat was an IO and had trim and outdrive fluid but just a bit of lube on a splined shaft. It is but it has a gear oil res. Never added a drop before this summer tho. 1 hour ago, Voodoo said: Really can only go out the tail, or if it's a remote reservoir it may be leaking in the pipe from there to the case. Pressure test it. When you say case do you mean the crank case? Quote Link to comment Share on other sites More sharing options...
Carlos Danger Posted September 3, 2023 Share Posted September 3, 2023 I would need to know more to help you out. The system is designed to slowly top off gear to about the top level screw on the top of the drive. Not a lot of places for the oil to get out unnoticed. Quote Link to comment Share on other sites More sharing options...
Gold Member Kivalo Posted September 3, 2023 Author Gold Member Share Posted September 3, 2023 3 minutes ago, Carlos Danger said: I would need to know more to help you out. The system is designed to slowly top off gear to about the top level screw on the top of the drive. Not a lot of places for the oil to get out unnoticed. We are wondering if a seal is beginning to go but not fully blown and therefor only leaking under power. Quote Link to comment Share on other sites More sharing options...
Carlos Danger Posted September 3, 2023 Share Posted September 3, 2023 4 minutes ago, Kivalo said: We are wondering if a seal is beginning to go but not fully blown and therefor only leaking under power. That is what normally happens but the oil reservoir might be masking the problem . The old mercruiser stearn drive before the reservoir tank used to heat up while you were using it and create a small amount of pressure in the case which had the effect of sealing up the seals. When you shut the motor down and the drive was under water it would cool quickly and make a small vacuum in the case that if the seals were bad would draw water into the oil. Easy to see this problem as the gearlube would end up milky. The reservoir tank system is open to the atmosphere pressure so the case no longer makes vacuum or pressure. So what you get is oil leaking out when it is running. The gearlube in the drive may not get milky because there is no vacuum. The test for leaky drives is a vacuum test not pressure. Pressure makes the seals tighter on the shafts which would mask a problem. Quote Link to comment Share on other sites More sharing options...
Gold Member Kivalo Posted September 3, 2023 Author Gold Member Share Posted September 3, 2023 1 hour ago, Carlos Danger said: That is what normally happens but the oil reservoir might be masking the problem . The old mercruiser stearn drive before the reservoir tank used to heat up while you were using it and create a small amount of pressure in the case which had the effect of sealing up the seals. When you shut the motor down and the drive was under water it would cool quickly and make a small vacuum in the case that if the seals were bad would draw water into the oil. Easy to see this problem as the gearlube would end up milky. The reservoir tank system is open to the atmosphere pressure so the case no longer makes vacuum or pressure. So what you get is oil leaking out when it is running. The gearlube in the drive may not get milky because there is no vacuum. The test for leaky drives is a vacuum test not pressure. Pressure makes the seals tighter on the shafts which would mask a problem. Ok, that makes sense. Next question. If the boat has been driven and just had the reservoir continually topped off have they damaged the engine? Quote Link to comment Share on other sites More sharing options...
Carlos Danger Posted September 3, 2023 Share Posted September 3, 2023 1 minute ago, Kivalo said: Ok, that makes sense. Next question. If the boat has been driven and just had the reservoir continually topped off have they damaged the engine? Engine and gearcase are two separate things. I don't know if you have an Alpha or bravo drive but the raw water pump could be an issue on an alpha if it has not been changed periodically. Quote Link to comment Share on other sites More sharing options...
Gold Member Kivalo Posted September 3, 2023 Author Gold Member Share Posted September 3, 2023 17 minutes ago, Carlos Danger said: Engine and gearcase are two separate things. I don't know if you have an Alpha or bravo drive but the raw water pump could be an issue on an alpha if it has not been changed periodically. Yeah I didn't think the gear oil would be routed through the engine, that doesn't make much sense. Just wanted make sure. Thanks for the input! Quote Link to comment Share on other sites More sharing options...
Frostynuts Posted September 3, 2023 Share Posted September 3, 2023 Follow the line from the bottom of the reservoir, and it will eventually end up at an elbow, which directs it out thru the transon. Unfortunately it is near the middle, so it is a bitch to reach. ,ve seen those crack over time. Check the elbow closely, look to see if there is an outdrive oil on the inside of the transom area, and in the bilge. If there is, that,s the area the leak is in. 1 Quote Link to comment Share on other sites More sharing options...
Voodoo Posted September 3, 2023 Share Posted September 3, 2023 I've got digital manuals if you need one. Drive alone is 18MB so I don't know if I can post it here Quote Link to comment Share on other sites More sharing options...
Gold Member Kivalo Posted September 4, 2023 Author Gold Member Share Posted September 4, 2023 21 hours ago, Frostynuts said: Follow the line from the bottom of the reservoir, and it will eventually end up at an elbow, which directs it out thru the transon. Unfortunately it is near the middle, so it is a bitch to reach. ,ve seen those crack over time. Check the elbow closely, look to see if there is an outdrive oil on the inside of the transom area, and in the bilge. If there is, that,s the area the leak is in. No oil in the bilge, checked there first. I will take a look and see if I can find that elbow tho. 20 hours ago, Voodoo said: I've got digital manuals if you need one. Drive alone is 18MB so I don't know if I can post it here A link or the actual digital files? Quote Link to comment Share on other sites More sharing options...
Voodoo Posted September 4, 2023 Share Posted September 4, 2023 2 hours ago, Kivalo said: No oil in the bilge, checked there first. I will take a look and see if I can find that elbow tho. A link or the actual digital files? Shoot me a pm if this doesn't work. Service Manual #06.pdf Quote Link to comment Share on other sites More sharing options...
Carlos Danger Posted September 4, 2023 Share Posted September 4, 2023 1 hour ago, Voodoo said: Shoot me a pm if this doesn't work. Service Manual #06.pdf 18.35 MB · 0 downloads Yea if he has a reservoir he will not be talking the MR drive it will be a Gen2. Quote Link to comment Share on other sites More sharing options...
Voodoo Posted September 4, 2023 Share Posted September 4, 2023 3 hours ago, Kivalo said: No oil in the bilge, checked there first. I will take a look and see if I can find that elbow tho. A link or the actual digital files? Got a serial number off the drive? the manual is broken into 30 ish pieces Quote Link to comment Share on other sites More sharing options...
Voodoo Posted September 4, 2023 Share Posted September 4, 2023 27 minutes ago, Carlos Danger said: Yea if he has a reservoir he will not be talking the MR drive it will be a Gen2. 👍 I’ll scan the other 30 or so chapters. Quote Link to comment Share on other sites More sharing options...
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