Miss Vegas runs great for 1 min then falls flat

[Christopher Moore]

Like the title says. This is the case after a flip over. Start it runs great for about 1 min then act like its at half throttle. We have adjusted the mix all over the place and it still runs the same. I am hoping we did not kill this brand new motor (yes it had 8 tanks through it before this proper break in).

I am wondering if we got water in the crank case and it is boiling a min in and causing these issues. But maybe somebody has an Idea.

BTW this is a Super Tiger .18

 

[TimothyJones]

Water in the fuel,maybe.

Water in the radio box/servo's.

After that happens be SURE to bow the motor out really good and restart it till it gets hot.

 

[Christopher Moore]

Cleared lines, box was tight no water in there. It ran 5-6 times after the blow over so I think it got nice and hot. Thinking it maybe a exhaust leak some where. Going to have to do a system pressure check I guess.

 

[Kevin Krogness]

Maybe to lean....

 

[Christopher Moore]

we have been almost 1 turn in both directions. At first it gives the indication of lean/rich until it reaches that 1 min or less mark then back to the same old bog. no matter what the needle is set at. It was running perfect at 3.75 turns out before the blow over. Seems a bit rich but it was keeping up and sounded good like my Miss V.

Oh yah and we have used 2 new plugs so that's out also and they looked brand new so it was running perfect mix wise.

I think we have figured it out. Checked all the lines and what not and found the nipple on the exhaust backed out 1/4 turn allowing air to come out on the blow test (super professional) tightened up now. So it seems maybe the pipe gets heated up and allows pressure to escape faster after about 1 min of running.

Will see this weekend.

 

[camaroboy383]

check the head button for deto..seen many of them st .18's with peppered buttons.... rear bearing failure will cause those symptoms also.. be sure it is o.k..

 

[Christopher Moore]

Will check those also. Thanks Guys any more input is welcome that's how I learn.

 

[Dick Loeb]

Get rid of the stock tank and put a 8oz dubro in its place

 

[camaroboy383]

Get rid of the stock tank and put a 8oz dubro in its place

i agree with dick on this one for sure.... could be the tank leaking pressure if its the stock one......

 

[Christopher Moore]

It's brand new stock one. The last tank did leak but has been replaced. I told the owner to replace it with a 8 oz like mine but he wont listen and likes the flip lid. At this point its not the tank we did a 2 psi pressure test on it and no leaks.

 

[Jeremy Linney]

I would still replace that tank with an airplane style tank. You could have an internal leak in fuel pickup in tank. This will not show it's head until fuel level drops a little allowing carburetor to draw air bubbles. Bearings would be my next guess.

 

[Christopher Moore]

Ok will check it out, I will see if I can get him to switch tanks. This weekend we will find out. I may order a bearing just in case also.

 

[Ted buckley]

Chris, I used to have one of these. If the above fails, what kind of pipe/exhaust connector do you have running from the end of the pipe to the exit of the back of the cowling or transom? Is it too small? is there a bend in the tube? I took mine off or went with a larger dia. tube and it stopped doing what you explained above.

 

[Christopher Moore]

Its a all stock setup. So the stock diameter tube. It does not appear to be bent or pinched. But I am seeing how the exhaust does cause these sort of issues through out all types of engines.

 

[osracer]

Pull the back plate and check for a cracked connecting rod at the crank end. Bill

 

[Christopher Moore]

I did take a look at the connecting rod when I checked for water in the case. It did not appear to have a crack or any issues. It seems to run good not under load for 5-6 mins with gravity feed water system. The true test will be Sunday when we hit the lake.

 

[SayMikey]

Check the water lines good and maybe make sure the pipe is not full of water

 

[Christopher Moore]

Replaced the lines with fresh line. Pipes been out about 5 times since blow over.

 

[Ted buckley]

I did take a look at the connecting rod when I checked for water in the case. It did not appear to have a crack or any issues. It seems to run good not under load for 5-6 mins with gravity feed water system. The true test will be Sunday when we hit the lake.

So, whatever happened with this - Christopher? Sunday has been long-gone and passed? :blink:

 

[Christopher Moore]

Still had the same issue. Thought I would call Tower to see what they said. After explaining what was happening they said they will just replace the engine. So it shipped Wed's. Hopefully no issues with the new one.