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55" Scarab with ops 90 questions

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55" Scarab with ops 90 questions

Old 04-28-2015, 02:37 PM
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Savagecrazy
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Default 55" Scarab with ops 90 questions

So I had a 55'' nice condition scarab come into my possession recently. it has a 15cc ops 90 nitro engine that requires one hell of a starter to get it going. I have run it on the bench once with the help of a 1/2 inch drill to get it going. My question is simply this. Sell the boat out right, spend the $90 for the huge starter or pull the nitro and and replace it with a zenoah gas engine. I have a rio 51 so I'm good with going the zenoah way but open to the others also. I have several nitro engine trucks and a nitro boat so that way is good to. Just don't know about spending $90 on a starter. Any info would be appreciated.
Old 05-01-2015, 03:50 PM
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rcollector
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I think it all comes down to what you want. Gas is cheaper to run but you already have the nitro motor. That 90 nitro will burn a lot of fuel I would buy a real good starter, use the nitro motor and you can use the starter on zenoahs too. I for one will not be pull starting any of my boats . I got starter pulleys on my zenoahs but I am not as young as I used to be and my arms hurt... besides it's not a bad idea and you can't go wrong having a good starter around . If you already have a gas boat why not try and see how you like nitro.
Just my thoughts

Last edited by rcollector; 05-01-2015 at 03:55 PM.
Old 05-02-2015, 06:48 AM
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There is no wrong answer here at least. If you are comfortable with the conversion I'd go with gas, save the $90 for the starter and sell the OPS.

RIck H.
Old 05-02-2015, 08:14 AM
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Savagecrazy
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Ok next question is has any one done a nitro to gas conv. Wondering what has to be done and so on.
Old 05-02-2015, 10:11 AM
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On a boat that size I can't see how it would be all that difficult. A lot depends on your building skills. Maybe a heavier drive shaft which would mean a new stuffing tube, different motor mounts but I don't see that as much of an obstacle either. I don't run any gas boats yet, planning to do a cracker box soon, but the ones I've seen have been very impressive. It will cost you some money but the difference in fuel cost would be noticeable pretty quick if you run it much. I'm paying $18-35 a gallon for nitro depending on percentage. Gas/oil is under $4. Adds up fast. I suspect you could recover most of the new engine cost by selling the OPS. Playing devils advocate though, I love nitro engines and enjoy running them enough I don't mind the fuel cost. We have so many good options now, it's the best time ever to be in this hobby.

Rick H.
Old 05-02-2015, 12:38 PM
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Savagecrazy
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Thanx for the info Rick. I like my rio but also like my nitro boat. I think in this case a gas swap would be a cost effective move. It also has a large flex shaft like my rio so I think it will be good that way. I have built every thing from model rc kits to 700 hp mud trucks so I'm good in the fabrication dept. so any idea what the ops would go for? Thanx in advance... Chris.
Old 05-02-2015, 05:45 PM
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Ron Olson
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The bad. OPS .90 parts aren't getting any easier to find. Nitro is expensive and that engine will burn a lot of it. Loosen the glow plug as that'll lower the compression until you get it started. I've got both a Dynatron and a Model 4 and have to use 24 volts to crank over big engines, 12 volts won't do it.
The good. It shouldn't be too bad to drop a gas engine in it. The boat should already be set up with a 1/4" drive. Gas engine prices are dropping for Zenoah's or their clones.
Motor mounts and other parts you can get at reasonable prices. I get a lot of those from www.zippkits.com . www.gizmomotors.com has very good prices on Zenoah's right now. I recently got one for $167.00 as I'm not a Zen person but it was too good of a deal to pass up.

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