Vc460 vapor locking

general01

Like the title says
I have had this happen multiple times

It was in the 80's today and I was just cruising at low speeds and a few high speed bursts

The engine temp sensor read 170 till I started pulling a few hills(which it did fine) and back down the same hills(no problem)

When I was on the flat stretches of road I would do the bursts to(hopefully) help cool the engine some down a bit(no luck)

It vapor locked three times on the return trip home(one time was in a spot I was not very comfortable with being broke down in)

After the first time I had this happen I made a couple make shift shrouds around the head and jug to help the fan blow air over the engine but no luck it's still vapor locking
I have my fuel and return lines away from the engine as possible

It has me concerned about driving my cart on long trips with it doing like this

Any thoughts or ideas???

BGW

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raydhd

My fuel lines run very near my engine certainly ran it all last summer with no issues.I guess what I am saying are you sure it is vapor locking? Is you fuel pump all that it should be? One last note my clone seems really cool under the seat compared to the stocker that never vapor locked either.Maybe some others will weigh in here.

general01

I am positive it's been vapor locking

I have seen this before as I own a classic car and know the signs

I have a brand new pump and it's not been problematic as I had it on the cart before the swap
Another thing was I could tap the choke and it would try to turn over(odd but true) but there was air in the lines due to vapor lock

It was closer to 90 then I thought today(speedometer shows both ambient and engine temp)
I had the factory over the same temps and never a problem

Ps I was barely doing 12-15mph during the drive as I was enjoying the scenery during the drive except for the two bursts of speed which I did on straight flat roads

sho305

The engine comes with full shrouds and will overheat without them, so I do not understand what you mean with the shrouds. I run two clones in up to 95F heat here never had a problem, there is no way the fuel can get hot as carb is on a spacer.

You may have to run better fuel than regular in a 460 I'm not sure what final compression is. This will be worse in high temps.

general01

Mine didn't come with any shrouds around the head or jug of the engine(NONE) just the one around the flywheel/fan
You can see the pics of the engine on Vegas carts site for proof
I had to fab up some yet it still vapor locks
It got up to 90 today while I was riding it(that's ambient temp)
I run 100percent gas(no ethanol) and it's fresh so I doubt fuel can be the problem(may add some octane booster just to see if it helps or not)
The compression is 10.5:1 per Vegas carts specs

What gets me is it runs smooth and pulls strong till the temps get around 180 then it starts to vapor lock I know it's not seizing up(else my rear tires would gone by now given the amount of times it's done it)
It doesn't knock(yes I know how that sounds)

Ps the temp sensor I am using is on the top of the head away from the air from the fan
It's driving me nuts seriously as I can't truly enjoy my cart due to the issue

slonomo

I can't believe Vegas Carts sent you an engine without shrouds? Did you call them? I'm betting they will send you the tins. You can't run an air cooled engine without them IMO, will always run too hot.

Vapor lock? I would check the following....

Things That Contribute to Vapor Lock

High Fuel Temperature (130 and above can be a problem)
Long Suction Lines
Restrictions in suction line (fittings and filters)
Lines passing high heat areas


Things That Prevent Vapor Lock

Cooler gasoline temps (100F or less is ideal)
Shorter (is better) suction lines
Eliminate sharp 90 degree fittings
Eliminate filters in suction line
Insulate lines in high heat areas

* If I had this problem I would shorten the lines, insulate them near engine and manifold, and eliminate metal lines since they conduct heat or insulate them with rubber to limit heat transfer. I would also install a reflective heat shield in front of the fuel tank to keep the fuel temp from going up during rides.

** I had an old car that would do this when the temp was 90 degrees or higher. The metal fuel line ran from one side of the engine bay to the other, over top of the engine. I removed the metal line, replaced it with a rubber line with braided ss cover. I also used some insulation material and covered the entire section, basically wrapped it and taped it. Problem solved. It's not that complicated of a problem to solve, it's actually quite easy. You just need to limit how much heat the fuel line is exposed to. If the line is metal and is next to a manifold or head, the line will pick up all that heat and when the fuel is not flowing it will transfer heat into the fuel.

raydhd

The only shroud or tin on the engine is the housing that contains the flywheel and starter handle.It extends up tp the cylinder head.Are you missing this? Are you sure you are not running too lean? Did you richen the mixture screw under the black plastic cover a turn or two?

general01

Sonomo Ray said what I was going to say the only shroud on it the one around the fan which holds the pull start

Now I did wrap the fuel line(both main and return) around the engine but I still have them routed away from the engine after I got back and am going to take it from another drive and see how it does

Ray I have the screw out around one turn per Arron's advice but am going to try different adjustments and see how it does in the hotter temps

slonomo

I use a laser thermometer to check the temp of the engine, etc. You could use one to check the temp of the fuel line. If the outer part of the fuel line is below 100 degrees you should be ok. The inside will only be cooler. If it's above 100 degrees you need to shield it or insulate it.

general01

Will a infared one work for that?

I have one for my nitro and gas powered rc cars and truck