Steve-in-SEA
New member
BEHEMOTH was recently re-powered with a Suzuki DF50A.
I thought I'd share initial impressions and info, in case it helps someone else.
This new motor replaced a 2005 Honda BF50A which had become unreliable (due to carb issues that few mechanics could fix or wanted to take on).
The mechanic put a Suzuki prop - 3 X 11.25 X 15 - on the boat and sea trialed it as best they could given the weather at the time. The expectation was set that after I put some hours on it, we trial it again to determine if it needs a different prop and/or a permatrim-type device (which the Honda had).
So far, I'm loving it. It's much quieter than the Honda, to the point where I have to check the telltale if it's running when at idle.
I opted for the Suzuki SMG4, which is their small (4") rectangular multi-function display. It's a $500(?) upgrade from the usual 3 instrument analog option, and well worth it, I think. The main display can show: Speed Over Ground, RPM, MPH, trim, engine temp, and gear position.
You can customize it, and also dig a little in the menus to see: voltage, engine hours, trip info (distance, gas used, engine hours). If I had a gas tank sender, it would show the state of the tank.
The SMG4 also connects to the boat's NMEA2000 network. It uses GPS (from Chartplotter, also on the network) to compute Speed Over Ground, and makes some engine data available to other devices.
So now I have two blanks where the Honda's trim and voltage gauges used to go
I've observed these RPM/MPH correlations so far:
2000 RPM - 5 MPH
3000 RPM - 7-8 MPH
4000 RPM - 17 MPH
4200 RPM - 20 MPH
5000 RPM - 24-25 MPH
At 20MPH, I think I'm seeing 9.8 MPG.
I've had it up to 28 MPH (didn't catch the RPM); that required very little trim. I'm not sure I have the nerve to try to WOT it. Honestly, I think a 40HP unit would have been just fine
It appears very sensitive to trim/tilt, more so than the Honda... perhaps becauseHonda was fitted with permatrim fins? A little bit of tilt goes a long way. Once or twice, in bumpy water, it seemed that the prop lost its bite, which I don't recall happened as often with the Honda. Maybe a permatrim is in its future...
It seems to "hole shot" reasonably well, but TBH I'm no expert here.
It's nice having a flush port, instead of having to use the mouse ears!
All in all: happy so far.
(I did have a little "episode" with the new motor wherein it would sputter but not catch after switching tanks. Fortunately this happened in Swinomish Channel (near Anacortes, WA - just past the anchorage with the huge tankers... and not, say, in Deception Pass). I wasn't able to get it running, so I switched to the kicker and made for La Conner further down the channel. Diagnosis: the connector on the tank was slightly corroded, creating enough friction to make me believe that I had a good connection. It wasn't, and the engine was sucking air. The external fuel filter, and the internal low pressure filter, were both empty. This was 90% user error, 10% mechanical. A little more presence of mind and I would have figured it out in a minute. Good thing for the kicker, though.)
FYI / Hope this helps / happy to answer questions, and open to any advice/recommendations folks might have!
Some photos here.
I thought I'd share initial impressions and info, in case it helps someone else.
This new motor replaced a 2005 Honda BF50A which had become unreliable (due to carb issues that few mechanics could fix or wanted to take on).
The mechanic put a Suzuki prop - 3 X 11.25 X 15 - on the boat and sea trialed it as best they could given the weather at the time. The expectation was set that after I put some hours on it, we trial it again to determine if it needs a different prop and/or a permatrim-type device (which the Honda had).
So far, I'm loving it. It's much quieter than the Honda, to the point where I have to check the telltale if it's running when at idle.
I opted for the Suzuki SMG4, which is their small (4") rectangular multi-function display. It's a $500(?) upgrade from the usual 3 instrument analog option, and well worth it, I think. The main display can show: Speed Over Ground, RPM, MPH, trim, engine temp, and gear position.
You can customize it, and also dig a little in the menus to see: voltage, engine hours, trip info (distance, gas used, engine hours). If I had a gas tank sender, it would show the state of the tank.
The SMG4 also connects to the boat's NMEA2000 network. It uses GPS (from Chartplotter, also on the network) to compute Speed Over Ground, and makes some engine data available to other devices.
So now I have two blanks where the Honda's trim and voltage gauges used to go
I've observed these RPM/MPH correlations so far:
2000 RPM - 5 MPH
3000 RPM - 7-8 MPH
4000 RPM - 17 MPH
4200 RPM - 20 MPH
5000 RPM - 24-25 MPH
At 20MPH, I think I'm seeing 9.8 MPG.
I've had it up to 28 MPH (didn't catch the RPM); that required very little trim. I'm not sure I have the nerve to try to WOT it. Honestly, I think a 40HP unit would have been just fine
It appears very sensitive to trim/tilt, more so than the Honda... perhaps becauseHonda was fitted with permatrim fins? A little bit of tilt goes a long way. Once or twice, in bumpy water, it seemed that the prop lost its bite, which I don't recall happened as often with the Honda. Maybe a permatrim is in its future...
It seems to "hole shot" reasonably well, but TBH I'm no expert here.
It's nice having a flush port, instead of having to use the mouse ears!
All in all: happy so far.
(I did have a little "episode" with the new motor wherein it would sputter but not catch after switching tanks. Fortunately this happened in Swinomish Channel (near Anacortes, WA - just past the anchorage with the huge tankers... and not, say, in Deception Pass). I wasn't able to get it running, so I switched to the kicker and made for La Conner further down the channel. Diagnosis: the connector on the tank was slightly corroded, creating enough friction to make me believe that I had a good connection. It wasn't, and the engine was sucking air. The external fuel filter, and the internal low pressure filter, were both empty. This was 90% user error, 10% mechanical. A little more presence of mind and I would have figured it out in a minute. Good thing for the kicker, though.)
FYI / Hope this helps / happy to answer questions, and open to any advice/recommendations folks might have!
Some photos here.