Rovan 1/5 5b

[Phill2]

Mine looked exactly like a real 668

Most strange

 

[spents]

Most strange

think it just depends which batch of carbs there adding to the engines at the time phil,
i've had both chrome barb and plastic barb rovan 668's

 

[Phill2]

You're probably right Spents.
I've only ever seen the chrome fakes.

 

[skaterriese45]

I use 93 octane plus VP 2 stroke oil. Is this ok? a little over 5oz per gallon.

 

[Seandonato73]

Thats plenty of oil. Something like 25:1

 

[skaterriese45]

I don't get it guys. I got about 8 tanks ran out of it and it still take 25-30 pulls to get it to start. I guess they don't make a start fluid for these haha

 

[Phill2]

If I'm having trouble starting my cars esp with the 990 carb I just spray a bit of "Start ya bastard" automotive starter fluid through the air filter and it fires up on the first or second pull.

 

[skaterriese45]

If I'm having trouble starting my cars esp with the 990 carb I just spray a bit of "Start ya bastard" automotive starter fluid through the air filter and it fires up on the first or second pull.

Thank you! Do you order that online?

 

[Phill2]

I don't know where you are but it's an Aussie product
Your local auto shop should have starter fluid of some brand.
It's all the same - basically ether.

 

[Just Fishing]

Might have been just the timing when I bought it, but my rovan came with an actual walbro carb.
Or it was a really good knockoff that included the walbro name...
I was actually quite surprised it had one.
I also have their spiral diaphragm ready and waiting to install once it comes time to rebuild it.

If your new to two strokes, especially things like gas leaf blowers and gas trimmers, there is also a method to help them start faster.
With the standard pull start, it helps to get some tension and then give it a solid and quick tug to get that engine spinning.

Search youtube for "how to properly start a chainsaw" to get an idea.

 

[RoushSport]

Interestingly, my 30.5 cc motor came with a 997 carb.....???

 

[Seandonato73]

Walbro makes carbs for rovan. Emailed a tech there and he conformed it. They are just made to rovan specs.

 

[Phill2]

Interestingly, my 30.5 cc motor came with a 997 carb.....???

According to the specs it's the same as a 668.

Walbro makes carbs for rovan. Emailed a tech there and he conformed it. They are just made to rovan specs.

I wonder how they differ from stock?

 

[RoushSport]

According to the specs it's the same as a 668.

Good to know! Interesting that the stock settings on the 668: Low is 1 1/4 and High is 1 1/2, where as on the 990 (which I'm guessing is close to the 997) the settings are Low 1 1/8 and High is 1 5/8....unless the guide I'm referencing is completely off....

 

[Phill2]

The 990 has no choke and is a PITA to start.
I tried one on a Zen 29 and it's been sitting in the bottom of my toolbox ever since.
No noticeable difference in performance compared to a 668.

 

[RoushSport]

The 990 has no choke and is a PITA to start.
I tried one on a Zen 29 and it's been sitting in the bottom of my toolbox ever since.
No noticeable difference in performance compared to a 668.

I wasn't aware the 990 is choke-less (I'm new to 1/5th scale, Rovan, Walboro, etc). I'd imagine that would be a bugger to get started!!!!

 

[Seandonato73]

The 990 amd 668 are not the same spec of carb. The 990 has a larger venturi. The carb by itself won't necessarily make the engine run better or worse. On a 29cc it's over carbed. Your flowing basically the same amount of air at alower air velocity, which makes tuning a pain. The 668 in 30cc and below is an optimal choice imo.