Here’s one for the modern-era Optimus experts: I have three Swedish-made (with that amazing CEJN connector) stoves, all in similar condition. Two are basic Nova and one is the plus. No matter what configuration of jet and pump I use, the plus takes about 30 extra seconds to boil 2 cups. It’s never a race and I have no problems with a 2:15 vs 1:45 boil time, but simply as an anecdotal comparison, has anyone else noticed that the Nova beats the Nova+ or is mine “unique”? I checked the Plus’s spindle and orings are good and the spindle itself is carbon free. No notable obstructions, just a slightly slower boil. I thought maybe the slightly longer hose might be a factor?
@paultee I have 2 +'s and a bunch of Nova's and one of the Nova+'s does put out less than the other one. I'm actually considering putting it in a Trangia 27. It's probably just a jet/nipple issue. Mike
@HunterStovie Well, I’m glad I’m not alone. I put a new jet in and it was identical to the old one. In every way an ideal flame, just a little less power—and that actually does seem like a nice reason to put it in a Trangia (which I generally just use with alcohol or the gas adapter), but more likely the stove I take with an outback oven because it simmers incredibly well and has that distance to adjust the flame.
@paultee Have you compared how control spindles look? Maybe Nova+ spindle restricts fuel flow more since fuel goes through the control spindle and comes out from small hole. That could also cause pressure drop. In this thread Optimus Nova+ Swedish made ca 2007/08 there following picture: Fuel flow might be slowed since flow needs to change direction in very tight space when fuel flow comes out from spindle hole and starts to go to burner direction.
I don't get a simmer out of my Nova, just can't get the valve shaft to move and stay, if you move it to where it needs to be to simmer, it won't stay. You have to move the shaft past the simmer point, then the flame goes out. Have tried graphite spray on parts to no good. Much prefer my MSR Dragonfly with Dragon Tamer silent cap. The Nova is pretty loud. Duane
Maybe rubber/silicone o-rings stick onto spindle and pull it back direction after spindle is turned? Maybe MSR "sealing care/lubricant oil" could help to that problem.
@Afterburner This is actually a very interesting thought. The Nova+ does have some kind of nearly imperceptible fluctuation while turning the hose. There are "sweet spots" where it clearly goes down and up despite the spindle being turned further to wide open. Also interesting, when it's opened to maximum, it actually ends up being weaker till you pull back a bit (the effect it similar to a 111 when you reach the first moment of the cleaning needle coming up, though I know it's not the same design--just the observed effect). An interesting stove. I might give it a carb cleaner bath and replace the blue o-rings just to have a task!
I gave the stove a further cleaning, and it's clean as a whistle. New blue orings (why not after 15 years) didn't change anything, and I kept the old ones as they're still great. Giving it 50% more pumps vs what I give Nova for the same fuel canister/fuel volume bumped the boil to just under 2min for 2 cups. Still a great stove that will work for years to come, and thanks to all this poking around I also ended up rebuilding the sluggish CEJN female end (shoutout to @presscall for the detailed teardown) then swapping it out of the sketchy glued NRV pump to a current one that was collecting dust. Now I feel a little better taking Nova/Nova+ out without a spare pump. I do think @Afterburner nailed it on the restricted flow hole on coming up with a reason one might see a slight performance difference in the Nova+ when all other things are equal.
By a pure stroke of luck a guy near me was selling two hoses (one CEJN and the other bayonet) and a post-revision new bayonet pump. I bought them last night all for less than half the price of a pump and swapped the hose. It completely changed my Nova+ behaviour. No up-down flame depending on spindle position. It's perfect now. I boiled 2 cups in 1:25 (with a heat exchanger pot I used with all tests). I looked closer at the old spindle and found indentations. Are these grooves even capable of affecting the flow of fuel? There were never any leaks. The marring you'll see is on the metal directly next to the o-rings—on both sides of the stove-facing oring. I'm curious what people think.
Threads and grooves that are cut through the threads look quite dirty. That might affected fuel flow. If there is more dirt in threads that are in stove side/end that might have caused weird symptoms when control spindle was turned.
I think the pic might be deceiving—coming down to angle and low resolution. I’ll give it another carb cleaner dip, but this is up to light:
Later picture speindle looks more clean! I have used fine steel brush to clean the threads and dental probe to scrape off any dirt from "fuel flow" grooves that go through the threads.
@paultee I received a newer Nova+ yesterday from the Bay of Evil. It was used but not very much. Output is 75-80% of my other Nova+'s which is probably why it's not very dirty. It's not the jet, a plugged filter, or a pump issue as I tried a spare pump. Any way I slapped it into its new home a Trangia 27 like I was going to do with the other one but that one is in a Trangia 25 now. Mike
That’s the right approach! I did the same thing with mine. Last year I found great deals on hard anodized Trangia sets and they’re a wonderful match with the Nova I was initially frustrated by. Glad others are still enjoying this stove. Despite owning a Polaris, the Novas from Sweden-made years bring me more joy (and generally smoother performance). That said, my local outdoor store had a Polaris on clearance with an open box discount so I <sigh> couldn’t resist it for $94USD equiv! Oh well!
