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1985 40 ELTK rebuild

B

bama

Contributing Member
Hello all. I am rebuilding one of mine. #2 scored badly this fall and #3 had some scoring. I found all the parts but had a question on the oiler. Do I need to worry about this failing? I see there was a conversion for a different oiler. Was that due to eventual wearing out? I am not sure why it failed. I didn’t not pressure test seals before tearing it down.

I have replaced seals o-rings, pistons, bored out to 10 thou over. It is coming together great and I just want to make sure I have done everything to keep it running for almost 40 more years.
 
Next question would be what caused the piston(s) scoring in the first place? Did you determine that? If its a Mikuni oil pump they're pretty much bullet proof. I've only had one have seal issue and start leaking oil into the bottom of the block when sitting, I replaced the pump since I refuse to go to 50-1 premix.
 
boscoe said:
Where did you read/hear of the oil pump conversion?
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When I was looking at the part number and finding it NLA, I stumbled upon mention of a conversion kit in a forum discussion. It was something I brushed upon and for safety I found a used one on the bay and have it coming. This year uses a KEhlin? I think that is the brand. Says Japan on it. MAde me think of the carbs I had on my 97 Polaris 700 SKS. The conversion was a mikuni. Now, trying to search, I don't see that information. Might have it on my other computer in the history.
 
fitz73222 said:
Next question would be what caused the piston(s) scoring in the first place? Did you determine that? If its a Mikuni oil pump they're pretty much bullet proof. I've only had one have seal issue and start leaking oil into the bottom of the block when sitting, I replaced the pump since I refuse to go to 50-1 premix.
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The Thermostat was original, but it was shooting out the pee stream when it went and when I restarted. The only thing I haven't replaced is the oil pump. I have the old driveshaft so was going to prime it and see if it pumps. There is a little seal at the bottom of the oil pump and I don't like its look BUT I can't find a part number on the ipl. I plan to pressure test and vac test the engine once fully put together. With the other oiler, I can compare flow.
 
bama said:
The Thermostat was original, but it was shooting out the pee stream when it went and when I restarted. The only thing I haven't replaced is the oil pump. I have the old driveshaft so was going to prime it and see if it pumps. There is a little seal at the bottom of the oil pump and I don't like its look BUT I can't find a part number on the ipl. I plan to pressure test and vac test the engine once fully put together. With the other oiler, I can compare flow.
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Forgot to mention that the original driven gear splines were almost wore off. I put a new driven gear in thinking it could have been that. I have a post or two from the fall about this. I will try to link it here.

1985 40 hp ELTK dropped compression in middle cylinder

I have a 1985 Lund Tyee 5.3 with factory installed twin Yamaha 40's. I LOVE this setup(except for graph transducer mounting). My last trip, the motor quit on me a few times at full throttle and when I tried to start it the last time, it didn't sound right. After the fishing trip, I tested...
www.marineengine.com
 
I got it all together and got it running. Ran mixed fuel until I was sure no air in oiler lines. Will do a break in when summer comes. Pics and videos coming. Wish I could make sense of the Oil pump part number being wrong. But, I know this one works.
 
I am bumping up this post to see if anyone knows if the Mikuni oil pump will bolt on to the 1985 40 ELTK that I have. The IPL says Mikuni from 90-94 on parts lists, but the number given for the pump is the Mikuni and not the Kehlin. Any help would be appreciated. This is confusing. I am rebuilding my other 40 hp this fall. My rebuild of the first one went very well and it runs so much nicer and quieter. Just want to have this so I can leave it for my kids when I am gone. Was diagnosed with Pancreatic cancer this summer. Doesnt' mean I'm gone anytime soon, but a person can't but help think it is possible.
 
For what it is worth the original oil pump for a 40ETLK was replaced by an oil pump kit. Kit part number 6H4-W1320-0900. Which may very well be the Kehin to Mikuni conversion.

Kit is no longer available from Yamaha USA but there seems to be one on Ebay. https://www.ebay.com/p/1828413142
 
boscoe said:
For what it is worth the original oil pump for a 40ETLK was replaced by an oil pump kit. Kit part number 6H4-W1320-0900. Which may very well be the Kehin to Mikuni conversion.

Kit is no longer available from Yamaha USA but there seems to be one on Ebay. https://www.ebay.com/p/1828413142
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Heck yeah. This is the pump and adaptor then? Should last as long as I need it to...and maybe my oldest boy. He sure loves this boat.
 
Update: Almost done with rebuild on my 2nd of 2 40ELTK's. Doing the upgraded oil pump kits as mentioned above. They come with small plastic filters or one way valves except I can't get air to go either way when I blow in them. Can anyone tell me what the purpose of those very small filters are?
 
I believe those are check valves. To prevent oil from flowing back down to the oil pump. Ideally they will have a marking on them indicating the direction of oil flow.
 
boscoe said:
I believe those are check valves. To prevent oil from flowing back down to the oil pump. Ideally they will have a marking on them indicating the direction of oil flow.
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Thanks, Boscoe. I had to put some pressure to get them to work,but now they do. Getting close to hearing it run again!
 
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