jethobby new gas boats

[jon_sg]

saw some new gas boats at jethobby this week.

wonder if how fast can they go and how reliable is the gs260 gas engine?

anyone has used any of these boat before?

thanks for any input!

[Palladine]

I just bought one from them SPYDER

Come to PP this Sunday as I will be maidening my Spyder. Built wise on the hull pretty good workmanship, except I need to apply epoxy on all the stringers as they were stingy on it.

[jon_sg]

missed

I couldn't make it yesterday.

anyway, thanks!

[Doraemon]

I don't know about the engine that comes with the Spider, but the JZ260M that comes with the Arrowshark series of boats is a copy of the Zenoah 260 PUM (all parts can be interchanged). The JZ260M is very easy to start and tune. It's never quit on me once so far. Mine is still running on a rich "break-in" setting but should be able to start leaning out the high speed mixture soon (only burned about half a gallon of fuel so far). I don't expect it to set any speed records but the power, response and reliability has been quite good.

[jon_sg]

gas engine

thanks for the info on arrowshark engine. saw one at Jethobby the other day priced at $320.

by the way, how many tanks of fuel do you run for the break-in process?

does the saliva test on nitro engine (to test if it is overheated) works on gas engine too?

[Palladine]

Saliva Test

Pls don't use your tongue for the saliva test These engines are supposed to be water cooled so might have a different set of citeria. So are you opening your wallet to grab a gas boat ?

Our Race Day is 29 April, time enough to run in and prepare for a good race.

[jon_sg]

will be getting one from jethobby soon.

do you use the leaded or non-leaded petrol?

[Palladine]

Both can be used as GAS engine (weed wackers - actually) differs from car as there is no catalytic converted to be destroyed. Go green - use unleaded.

2T Synthetic Mobil One is supposed to be the best, someone in the forum used Castrol 2T but found black lumps of residue. I like the characteristics of Castrol Oil due to it high temp and stickness to metal, ideal for nitros but I am using ESSO (sweet smelling) for running-in.

[Doraemon]

I have done al lot of research on the web to see how long it takes a gas engine like a Zenoah 260 to bed-in and have come across a wide variety of opinions. For example, the Zenoah engine manual states that no specific break-in is required... the engine is supposed to get more and more powerful as time goes by However, most gas boaters in the US don't believe that and will run 1/2 to 1 gallon of 2T mixed at 25:1 through the engine before settling on their final fuel mixtures.

As to whether a gas engine is overheating... you can check the spark plug after a run to see if it is a healthy colour. You can also shine torch light into the cylinder and check for scuffing and other tell-tale signs of overheating or over-lean running.

Palladine, which Esso 2T oil are you using? I think they have about 4 different grades Thankx

[Doraemon]

Our Race Day is 29 April, time enough to run in and prepare for a good race.

Yep, if you're getting a brand new boat, you have 2 weekends for engine break-in and sorting out any bugs you may find

[Palladine]

Hi Doraemon

I'm on 2T Low Smoke after this bottle I might move to Esso Gold which is double the price or Mobil 1 if I can find it.

[jon_sg]

2T oil

wow, synthetic 2T oil costs more than nitro!

is there any "after-run" or similar type of oil for gas engine? for nitro, I used to drip some into carb and piston head before storing away in hangar.

[Palladine]

Nope, not correct, 2T Esso cost me below $10 per litre, and you use 20:1 parts for running-in and 25:1 for normal. 1 gallon of petrol will be $6 (assuming 4 litres makes a gallon) so not more than $6.50 per gallon.

Looks like you are serious in getting the Gas Boat saw you EP boat up for sale. You the man

Like to suggest that when you get your boat -
Epoxy all the wooden stringers and transom
Fuel proof all the wooden parts as plywood although laser cut (very nice) is not marine grade and will peel on contact with petrol. Engine, fuel tank, RC box need to remove.

[Palladine]

No after run oil as like car engines.

Only nitros with castrol oil form a sticky lacquer coating that assist to seize your nitro engine.

[jon_sg]

thanks for the info.