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  1. Yanmar 3GMD: Rydlyme or other marine descaler in older engine

    Hi Sailnet, I've recently acquired a 30 year old Yanmar 3GMD which runs at 67C (152.6F) at the crankcase when revved to 1800rpm after a few minutes. This is a little hot for my liking as I'd like to try and get it to 2000rpm if possible - beating into 25knt wind in a very narrow and shallow...
  2. Yanmar SB8 issue/questions

    Hey all. I have an old inboard Yanmar SB8 in my Sun 28 that I am having issues with. First off, I am not very familiar with diesel engines and rely a lot on friends, and here, for help. So, the engine has seized. Pulled the head off and looked at the piston. Springs on the head were a bit rusty...
  3. Gallons per hour on Yanmar 27HP

    Thinking of buying a catamaran with dual Yanmar 27HP. The boat's tank is 50 gallons which seems small to me. How many hours should I expect to get, running single engine at a time, in normal cruising speed (assuming sail is down of course)?
  4. Yanmar 2GM20F Coolant

    Hey everyone, I have my first diesel - a yanmar 2GM20F. Yesterday the exhaust stopped producing water and the WC Alarm sounded within minutes of starting the engine before I even got out of the marina. I brought her back into the slip immediately and here's what I observed: The Coolant...
  5. Yanmar 2GM20F Maintenance

    Hello Forum, I am a newbie - just bought a '79 Catalina 27'. The original engine was a Petters (sp?) and it currently has a Yanmar 2GM20F inboard diesel. I've heard the engine is worth more than the boat. Ha! At any rate, I have scoured the web, and am not finding any kind of a simple...
  6. Belt deflection gauge for Yanmar 3GM30F

    I'd like to use a simple belt tension gauge like the Krikit to adjust the belts on my Yanmar 3GM30F. However the belt tension is specified as X mm of deflection with 10 kg of force, and I haven't found a gauge that I can use to directly measure that. What tool do you use to measure the belt...
  7. Yanmar 40 HP 3JH3E engine problems

    Hi Everyone The Yanmar 3JH3E 40hp in my boat has been a great work horse. Last season I replaced the primary and secondary filters and I have bled the system. What I am finding now is that after running the engine in gear for 30 minutes or so, it tends to just drop power and then rev up...
  8. Prop Not Turning -- C&C 27

    C & C
    The prop on our C&C 27 is not turning. We documented it in a youtube video: (You have to copy and paste the link because I can't post a link because I'm too new here. I promise it's not spam or anything nefarious.) It's a folding prop, as you can vaguely tell...
  9. 1gm10 low oil pressure after changing water pump

    Hello, I just bought a Flicka 20 with a yanmar 1gm10 engine that hasn't been maintained for about ten years(boat and engine). She starts though. I had a mechanic friend help me run through the basics. We cleaned out the water lines, changed the oil and found water inside when checking the oil...
  10. New paid sponsor

    Introduce Yourself
    Hello, We would like to introduce ourselves to your community. Our company mainly focuses on marine generators, but from time to time we get engines and sail drives as well. Also if you need any parts feel free to give a shout and we will do our best to get you the best prices and speedy...
  11. YSM12 Blues

    I am sure this topic has been discussed but I have not found it in the search so here it is again, my apologies for redundancy. I have an 80s model Yanmar YSM 12. Been a great motor for the last two years, always cranked and ran like a dream. I had to re-thread the return line (small metal tube...
  12. Yanmar loses RPM in gear

    I have about 500 hours on my 3GY20 Yanmar. I've had no problem with it. I've always been able to run it up to 3400 - 3600 RPM. I prefer to run it about 2700 RPM for comfort and vibration, and that seems to optimize speed/efficiency. I try to run it at 3000 periodically to clean the...
  13. Yanmar heat exchanger leak??

    I have a 1996 4jh te (serial #12285) and think the heat exchanger may be compromised. Here´s what happened. Started with a big mistake - we tried to fill the hot water heater heat exchanger lines at the hot water heater using a hose and a T fitting. (hot water heater is above the engine). We...
  14. Southest Yanmar Dealer

    Southeast Yanmar Dealer Looking for a recommendation on a good Yanmar Dealer for parts that has Florida in its Region. Prefer one that has many parts available via online store. Thanks in advance Spencer
  15. Transmission output flange fell off Yanmar 2QM15 - Theories re: why?

    Gear & Maintenance
    Hello, I recently had the output coupling from my Yanmar 2QM15 transmission fall out while underway (we didn't hit anything), disconnecting the prop shaft as a result. I'm in the process of undergoing repair, but I'm concerned that I may only be addressing the symptoms without isolating the...
  16. Kanzaki-Carl Hurth KBW10 Oil Seal replacement

    wondering if anyone else has had to replace this o-ring and metal seal on the output shaft....if so any pointers on where to get these parts or the process itself would be greatly appreciated...oh, I am also out in the bahamas currently so its been making finding information and parts a little...
  17. CCA - Cold Cranking Amps question

    I have the old faithful Yanmar 3 cylinder 3GM30? diesel on my cat. The starting battery probably needs replacing (won't charge over 12.7 volts) but I thought I would just take the battery from my car as a spare. The CCA on the car battery is fairly high - 720 CCA. My question is whether the...
  18. Yanmar 2QM15 Rebuild

    Gear & Maintenance
    Hi, In early July, I came to my boat after being away for three week and found the engine seized. It was locked up solidly, in that it would not budge even a little bit after soaking the cylinders with Marvel Mystery oil for several days. It turned out to be a blown head gasket which let...
  19. Yanmar Alarm Panel Problems

    Hello All. I have recently purchased A Hans Christian 33T with a Yanmar 3QM30FG 30 HP. I have not had the boat in the water long and am still working out the bugs. I was cruising last night low RPM and my belt broke. I maneuvered the boat into a safe direction for maybe 3 minutes and shut her...
  20. Looking for a Yanmar SB8 diesel

    We recently purchased a 1977 Hunter 27, which has been sitting in the cradle for the past 3 years. It was too good of a deal to pass up. Started the engine about 2 weeks ago for the first time. Fired right up, idles nice, alternater charging, water pumping out of the exhaust, and out of the...