Yamaha 25-ii retrofit: Piccolo

Sep 8, 2021
15
yamaha 25 mkii tall rig vancouver
The throttle cable to the Morse mt control snapped on my 25-II, and I’m in the process of replacing it; It was easy enough to pull out of the bilge.

The picture attached is the part that rotates and attaches to the 33c cable (the smaller part with the cotter pin). Could anyone confirm the larger rotating part is meant to be bent so much? I think the top part (circled) should be flat, and my copy has been bent by accident. Many thanks !

Piccolo
 

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Mar 6, 2008
1,078
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
It appears from your photo that you are right that the section near your finger is bent due to excessive force, but the bend near the hinge is made by a machine at the factory. I would recommend replacing this piece instead of straightening it as that would weaken the metal.
 
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Sep 8, 2021
15
yamaha 25 mkii tall rig vancouver
I will post my ongoing repairs / maintenance tasks for Piccolo here, to share findings and ask for help too.

The control line was pretty easy to fix. It cost about $50 USD, and was easy to thread through the bulkhead and hull. One thing that I did find confusing was finding the cable, as the cable was originally made by Morse, than that company got sold, bought by others, having names such as Telefax, SeaStar, Sierra International, and now Dometic. They are still the Morse cables.

My next task after fixing the control line, is to tackle the exhaust riser, mixer elbow, and muffler. Pics shown before and after removal + some cleaning up with a small screwdriver. To be honest, I'm leaning towards replacing the whole shebang as I don't trust it, even if I do manage to get the surface rust off. The mixer elbow downstream side had minor carbon buildup, but since I haven't been able to get the parts apart, I can't really see how bad the carbon buildup is inside.
 

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Sep 8, 2021
15
yamaha 25 mkii tall rig vancouver
I am looking at purchasing the HDI stainless steel mixer elbow and adaptor joint. One concern I have is that my original adaptor is 3" long before the threads. The HDI model has a shorter threaded model. I know that the elbow has to be above the waterline, so should I be concerned? Will adding a black pipe between the adaptor and the mixer elbow to gain the needed space do the trick?
 
Sep 8, 2021
15
yamaha 25 mkii tall rig vancouver
Last part of the exhaust setup, is the muffler. I have what I think is the original waterlift muffler, which was a really pain to get out of the boat. A friend gave me a Vetus, but the intake diameter is significantly smaller than the old muffler. Since it's downstream, and the water is not pressurized, I was thinking it should be fine, but am looking for comments / advice. I could put the old muffler back, or buy a new one, if the Vetus is risky?
 

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Sep 8, 2021
15
yamaha 25 mkii tall rig vancouver
If anyone is looking for ysm8 / ysm12 Yanmar exhaust parts, here are the part numbers:
  • Manifold Gasket 104211-13201
  • Exhaust Elbow 104211-13070
  • Joint 104214-13580
  • Mixing elbow 104214-13521
 
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Likes: tfox2069
Jan 7, 2011
4,723
Oday 322 East Chicago, IN
Last part of the exhaust setup, is the muffler. I have what I think is the original waterlift muffler, which was a really pain to get out of the boat. A friend gave me a Vetus, but the intake diameter is significantly smaller than the old muffler. Since it's downstream, and the water is not pressurized, I was thinking it should be fine, but am looking for comments / advice. I could put the old muffler back, or buy a new one, if the Vetus is risky?
What is wrong with the old muffler?

if it is serviceable, that is the path of least resistance.

Vetus is a well-known muffler. I have a similar water-lift exhaust on my boat with a Yanmar 2GM20F engine. How much smaller is the inlet than the exhaust hose? You need to have a tight, vapor free connection, or you could be pumping CO2 into your boat.

Also, not sure how a muffler is “sized” to an engine, and the exhaust hose (capacity for the WL).

Greg
 
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Jan 7, 2011
4,723
Oday 322 East Chicago, IN
I am looking at purchasing the HDI stainless steel mixer elbow and adaptor joint. One concern I have is that my original adaptor is 3" long before the threads. The HDI model has a shorter threaded model. I know that the elbow has to be above the waterline, so should I be concerned? Will adding a black pipe between the adaptor and the mixer elbow to gain the needed space do the trick?
I assume your mean that the nipple is too short (standard on the HDI elbow).

You can purchase a longer riser from HDI…


Also, note that (I believe) the nipple has opposite threads on each end…so a standard pipe nipple probably would not work.

1635895495042.jpeg


Greg
 
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Sep 8, 2021
15
yamaha 25 mkii tall rig vancouver
What is wrong with the old muffler?
Hi Greg,

Before I removed the exhaust and muffler, I believed the latter was rusting (see attached photo for the mess left behind). But it was actually the rusting exhaust riser, and the heat wrap disintegrating.

I'll have to check the muffler again for leaks, but I think your reasoning is right on - it seems re-usable.
 

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Jan 4, 2008
147
Yamaha Y25 mkII Long Beach, Ca.
Save the cast original exhaust manifold and replace the mixing elbow and coupling, black pipe works for me. I think of the mixing elbow/ coupling as sacrifical as they are prone to corroding and clogging up, lot of examples to be found on the forums. The mixing elbow as a generic part used on lots of boats.
I keep a spare on hand as well as waterpump/impeller. with the very long exhaust in the Y25 I figure better safe than sorry. I believe my coupler is 5" o.a.l. providing enough lift. don't quote me as that is a guess, I will have to measure. seems to me you should have a similar lift point in the exhaust near the transom due the unusual exhaust length.
Regarding the muffler it looks like mine so I am assuming it is standard. Only problem has been pin holes at the welds. I just maintain the catch pan under the engine. At some point I may fabricate a replacement of similar design just heavier wall thickness, has been a big enough problem as of yet.
Syntonos only uses the engine to get away from the slip or to deliver to the boatyard for bottom work. The YSM8 is a little workhorse.
Cheers
 
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May 20, 2013
14
Yamaha 25 Macau
I assume your mean that the nipple is too short (standard on the HDI elbow).

You can purchase a longer riser from HDI…


Also, note that (I believe) the nipple has opposite threads on each end…so a standard pipe nipple probably would not work.

View attachment 199775

Greg
I can confirm you will need GMR5 Stainless Steel Exhaust Riser.
I replaced mine last year too.
 
May 20, 2013
14
Yamaha 25 Macau
I am looking at purchasing the HDI stainless steel mixer elbow and adaptor joint. One concern I have is that my original adaptor is 3" long before the threads. The HDI model has a shorter threaded model. I know that the elbow has to be above the waterline, so should I be concerned? Will adding a black pipe between the adaptor and the mixer elbow to gain the needed space do the trick?
The mixing elbow model you need is the GM (it comes with a small 1/2" 90 degrees nipple). Not the GM2. You will also need the GMR5 Riser
 
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Sep 8, 2021
15
yamaha 25 mkii tall rig vancouver
I have an oil leak, without the engine being run, on the lower left side, collecting in the bilge. It appears to be collecting under the starter motor and where the clutch case attaches. I am seeing about a teaspoon of oil in the bilge when cleaning up. Oil is quite clean, so I think it's transmission oil.

Any suggestion on how to start troubleshooting this?
 

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May 20, 2013
14
Yamaha 25 Macau
I have an oil leak, without the engine being run, on the lower left side, collecting in the bilge. It appears to be collecting under the starter motor and where the clutch case attaches. I am seeing about a teaspoon of oil in the bilge when cleaning up. Oil is quite clean, so I think it's transmission oil.

Any suggestion on how to start troubleshooting this?
I suggest to start retighten the starter motor nuts.
If the leak presistes then replace the starter motor gasket.
Make sure the flanges surfaces are very clean and the studs are good (including their threads).
 
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May 20, 2013
14
Yamaha 25 Macau
I suggest to start retighten the starter motor nuts.
If the leak presistes then replace the starter motor gasket.
Make sure the flanges surfaces are very clean and the studs are good (including their threads).
The tightening torque should be around 25 N.m
 
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Sep 8, 2021
15
yamaha 25 mkii tall rig vancouver
Winter 2023 project on Piccolo is to clean the fuel tank. The previous owner had the boat for 10 years, and when he sold it to me said it hadn't been cleaned during his time. It was easy enough to remove the fuel tank, although I was surprised at how inaccurate the fuel gauge is - it read empty, and yet I had 1/3 of a tank to pump out. I was pleasantly surprised at pump out -- only about a cup of sludge. Degreased the tank with Simple Green Pro HD, and then used baking powder to remove exterior surface rust. But the real magic was citric acid (6 cups for the full tank); that removed much more surface rust both in and outside of the tank. Despite it being 45 years old, looks very healthy, with virtually no surface rust. Fuel hoses replaced too. Going to replace the primary filter. Have not yet located the second fuel filter, needs further investigation.

I do have an ongoing issue with the original waterlock muffler; it's exhaust is leaking. I read that some have replaced it with a Vetus, but I would love any advice on the size (2"?), and where it could be installed. Also heard the Vetus isn't that great because it's plastic... so alternatives would be great if they exist?
 
Sep 8, 2021
15
yamaha 25 mkii tall rig vancouver
Work done on Piccolo the Yamaha 25 ii tall rig this winter and spring.


  1. Emptied, and cleaned the fuel tank with detergents and then used citric acid to re-passivate it. New fuel hoses in addition to replacing secondary and primary filters
  2. Removed the gimballed stove, polished it with buffing compound, and then citric acid to passivate
  3. Repaired the wooden folding shelves above sink and stove
    1. Disassembled the piano hinges and the rusting zinc plated 1 inch hinges a PO had installed. The original piano hinges were seized and didn’t fold; causing screw mounts to slowly strip. But the hinges are high quality and have a bronze pin that was easily restored. Lubricated the piano hinges with tri-flow; and now they fold with ease.
    2. Sanded the peeling laminate off the folding shelves down to the wood, varnished them, and resurfaced with black matte contact sheets
  4. Removed my seized engine anode zinc carrier using an impact wrench with an 8-point 22mm socket after a breaker bar and wrench had failed to budge it, despite PB blaster
  5. Washed and shop-vac-ed all v-berth cushions and repaired the covers
Busy busy busy, but happy
 

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Dec 27, 2020
29
Yamaha 30 - Tall Rig Vancouver
Winter 2023 project on Piccolo is to clean the fuel tank. The previous owner had the boat for 10 years, and when he sold it to me said it hadn't been cleaned during his time. It was easy enough to remove the fuel tank, although I was surprised at how inaccurate the fuel gauge is - it read empty, and yet I had 1/3 of a tank to pump out. I was pleasantly surprised at pump out -- only about a cup of sludge. Degreased the tank with Simple Green Pro HD, and then used baking powder to remove exterior surface rust. But the real magic was citric acid (6 cups for the full tank); that removed much more surface rust both in and outside of the tank. Despite it being 45 years old, looks very healthy, with virtually no surface rust. Fuel hoses replaced too. Going to replace the primary filter. Have not yet located the second fuel filter, needs further investigation.

I do have an ongoing issue with the original waterlock muffler; it's exhaust is leaking. I read that some have replaced it with a Vetus, but I would love any advice on the size (2"?), and where it could be installed. Also heard the Vetus isn't that great because it's plastic... so alternatives would be great if they exist?

I have a Yamaha 30 (tall rig) and I'm looking to replace my muffler as well. YSM12 so pretty much the same config as the YSM8 - vberth engine. I've seen the Yamaha 25 engine bay and the muffler looks identical. What did you find as an alternative replacement. I couldn't find a Vetus or after market replacement that seemed to be the right choice. And what forums are you finding your info - be great to know!

Thanks!

Peter