R-21 Volvo D1-30 question

Sheepdog012

Well-known member
Joined
Jul 22, 2020
Messages
53
Fluid Motion Model
C-24 C SE
Hull Identification Number
fmlt2134c515
Vessel Name
Island Girl
Hi Folks, For those R-21 owners that have the Volvo D1-30F, I am wondering what RPM you like to cruise at? I was told by the dealer that those motors want to be run wide open (3,000 RPM) as much as possible. I have also read in the Volvo manual to run them 500 RPM below WOT, so roughly 2,500 RPM . Depending on how the Island Girl is loaded, 2,700 seems to be where she is happiest, although not the optimal fuel efficiency. Also, does anyone cruise at lower RPM's? I am trying to find a balance between fuel efficiency/motor longevity and concern about glazing up the cylinders or clogging up the riser with carbon. Any insights are greatly appreciated!
 
I cruise at 2200 because it gives me 6 knots of speed give or take 0.2 knots. I tow a tender ant it will not track well over 6 knots. This gives me a burn rate of 1.6 litres an hour.
 
2200 is my sweet spot where I get about 6 knots and can have a conversation. We run at 2700 if we want to go a little faster which gets us 7 knots to 7.5 knots. The engine runs really smooth at that rpm but it’s a little louder. I rarely run wot. I usually only do it for the last 5-10 minutes of my run as I was taught to burn off carbon.
 
1800 rpm seems to be a sweet spot for us. It gives about 5.5 knots at 0.5 gph, while minimizing the various buzzing and rattling noises from the fiberglass boat parts and pieces.

Larry
 
1800 to 2200 works great for Jersey Girl, but we do run at WOT occasionally.
 
Mine does:
1500 rpm, 5kn, 20nm/gal.
2000 rpm, 6kn, 10nm/gal.
2500 rpm, 7kn, 5nm/gal.
approximately.


Sent from my iPhone using Tapatalk
 
Very seldom run at WOT on mine. Going to and from fishing grounds I normally run 2700-2800 and this will give me 7-7.5 knots. 90-95% of the time I'm trolling so running 850-950 RPMs which is suppose to contribute to carbon build-up in the exhaust elbow, or so I'm told. Two elbow inspections, one at around 1400hrs and the most recent at around 2200hrs and the elbow has only had a light layer of soot, zero buildup,,,, so your elbow will probably be OK at any cruising speed. My trolling RPMs may cause other issues down the road but elbow build-up does not appear to be one of them,,,,, not yet.
 
Thanks all for the insights! Looks like I will be slowing it down a bit and seeing how it works out around 2200.

Be well!
 
I had the very same D1-30 in my 34' sailboat for 12 years. I loved it and ran it between 2000 and 2400 but the sweat spot for sound and efficiency was 2200 rpm. I loved the engine and it was the 4th motor I had in the boat over 37 years. All Volvo's and some not so good. The D1-30 started great every time...only issue was a little leaky fresh water pump. I swapped the original exhaust manifold to SS when new as I had two original ones fail and wanted to avoid that.

I have finally sold the sailboat and now looking for a 21 EC Ranger. I have posted such in the For Sale forum.
Prefer the D1-30 but would take a Yanmar if I can find the boat on the West Coast.
 
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