84 H31 I would be interested in hearing others experience with the Yanmar 13hp in the H31. Mine runs like a dream, with a little black smoke (working on that). Tuned my 16" 2-blade Max-Prop to get max speed of ~5 knots and still allow the thing to run at 3000 RPM's. With this undersized engine, I worry about getting in currents/headwind which could overcome the little girl. Has anyone done any serious crusing with this engine/boat combination? Also, I'd like to hear how other's boats perform compared to mine in terms of speed:RPM ratios. What was Hunter thinking when they used this engine in my 31? Thanks
- Status
black smoke...not good.
You most likely need a new mixing elbow. Also, check the air cleaner. That motor is now up to 18 hp. I have a 16hp version in my hunter 28.5 and can get 6.5 to 7 knots from it. Mine gets sluggish and emits black smoke when it time for a new exhaust elbow. It's a good reliable engine.
You most likely need a new mixing elbow. Also, check the air cleaner. That motor is now up to 18 hp. I have a 16hp version in my hunter 28.5 and can get 6.5 to 7 knots from it. Mine gets sluggish and emits black smoke when it time for a new exhaust elbow. It's a good reliable engine.
Hi Gary
My 1987 Hunter 31 Yanmar 2GM20F is rated 16 HP @ 3200 RPM. I'm running the stock prop, 2 blade 15" x 12. I can get it up to 6.7 MPH @ 3200 RPM, 2/3 throttle. At that speed it starts to push a little black smoke (clean prop). If I go full throttle after that, no increase in speed but a whole lot more black smoke. This year I had a lot of marine growth, by the end of August my prop was fouled. Could not get the boat faster then 4 MPH and a whole lot of black and I mean black smoke. So putty knife in teeth under the boat I went. With a clean prop I was back to my 6.7 MPH @ 3200 RPM, 2/3 throttle. If your mixing elbow is bad, you will not be able to throttle up to top RPM in neutral.
My 1987 Hunter 31 Yanmar 2GM20F is rated 16 HP @ 3200 RPM. I'm running the stock prop, 2 blade 15" x 12. I can get it up to 6.7 MPH @ 3200 RPM, 2/3 throttle. At that speed it starts to push a little black smoke (clean prop). If I go full throttle after that, no increase in speed but a whole lot more black smoke. This year I had a lot of marine growth, by the end of August my prop was fouled. Could not get the boat faster then 4 MPH and a whole lot of black and I mean black smoke. So putty knife in teeth under the boat I went. With a clean prop I was back to my 6.7 MPH @ 3200 RPM, 2/3 throttle. If your mixing elbow is bad, you will not be able to throttle up to top RPM in neutral.
What do you mean when you say....
"THAT motor is now up to 18hp"? Is my motor rated at 13hp at the prop or crank? Landsend, are you saying that we have the same engine? Patrick you are probably right, as I have noticed thru the year less speed. I think my prop is fouling quicker than I realize. However, in May when I hauled 3x's to adjust the max prop, with a clean prop, I could only make a little over 5 knots at ~3000 rpms. Like yours, I have noticed the last little bit of travel on the throttle doesn't seem to result in more speed. New air filter and the PO had just rebuilt, and the mixing elbow looks new and shiny. Maybe I need to stop assuming that it's clear and check it.
"THAT motor is now up to 18hp"? Is my motor rated at 13hp at the prop or crank? Landsend, are you saying that we have the same engine? Patrick you are probably right, as I have noticed thru the year less speed. I think my prop is fouling quicker than I realize. However, in May when I hauled 3x's to adjust the max prop, with a clean prop, I could only make a little over 5 knots at ~3000 rpms. Like yours, I have noticed the last little bit of travel on the throttle doesn't seem to result in more speed. New air filter and the PO had just rebuilt, and the mixing elbow looks new and shiny. Maybe I need to stop assuming that it's clear and check it.
Gary
I checked my Yanmar manual for engine output and it listed two specifications for the 2GM: 13.4 @ 3600 KW/RPM 18.2 @ 3600 HP/RPM I think the KW/RPM is the metric rating. Maybe your engine tag was marked metric.
I checked my Yanmar manual for engine output and it listed two specifications for the 2GM: 13.4 @ 3600 KW/RPM 18.2 @ 3600 HP/RPM I think the KW/RPM is the metric rating. Maybe your engine tag was marked metric.
My manual....
says: Continuous Rating: 13hp@3400rpm One Hour Rating: 15hp@3600rpm Apparently, the manual is only for this particular year model, as it only refers to 2GMF & 3GMF models. Nothing about the other hp models? So, I guess, the only 2 cylinder model they made for that year was the 2GMF13.
says: Continuous Rating: 13hp@3400rpm One Hour Rating: 15hp@3600rpm Apparently, the manual is only for this particular year model, as it only refers to 2GMF & 3GMF models. Nothing about the other hp models? So, I guess, the only 2 cylinder model they made for that year was the 2GMF13.
- Status