Ok, i'm stumpped.

I have a saito 80 (gk) that I used to run inverted on an old mustang. I have since stripped down the mustang and the engine has been sitting around for a while.
I decided to use the saito in my freestyle but can not get the engine to run up right on my test stand.

I have switch out plugs from the installed saito plug to an OS f plug, adjusted the valves, and cleaned the carb.

I can get the engine to start and idle but when I try to transition to high speed the engine dies. It will puff smoke sputter and die. I can go back to idle and it will stay running. I've tried adjusting the low in in both directions but it acts the same way each time. It will not get past mid range.

any help or needle settings are needed


thanks
steve

[b[Steve:

Several guesses.

Your carb probably has no low speed needle, but rather has a metering sleeve. Only the early ones had the needle.

Pull the HS needle and the throttle barrel. Using a spray can of carb cleaner or similar blow through the spray bar from the barre lend out through the needle mount. Put the needle back in only to the point of engaging the threads, blow through the spray bar again. Now stick the small tube on your spray can into the LS sleeve, blow out any congealed oil there. When you put the carb back together set the flat slotted end of the LS adjustment even with the flat side of the throttle lever, set the HS needle to 3 or 3 1/2 turns open.

The o-ring seal inside the body of the carb for the intake pipe doesn't give any trouble, but check the one at the head end carefully. This one can be trouble. Best if you just replace it, and at installation of the pipe be sure you have the metal washer outside of the o-ring, and put a light smear of RTV on the upper end of the pipe before you insert it into the head.

Third guess is the tank height. Be sure it's about centered on the spray bar.

Now when you're ready to restart don't bother with the low speed at first. The low and high speed adjustments are interdependent, except at full throttle, so the HS has to be set first. Go to HS peak, then get a rich drop of a couple hundred rpm. Now set the LS in the normal manner, rechecking the HS as you go. Should solve all running problems.

So, my guesses are 1, something you missed in the carb, and 2, an intake leak. Third obviously, is the tank position.

If you are still having a problem after this, assuming compression is OK of course, get the carb "Upgrade" kit from Horizon and install it.

Bill.

thanks Bill,
I'll give those a try later in the week.

steve

I didn't find an "upgrade" kit for the 80 but they did have a rebuild kit, same thing?

[b]Steve:

Horizon part number SAI80144 is the "Upgrade Carb, Rebuild Kit: 72-8" in the product description. Last one I got cost $11.39 plus postage. It converts the FA-72 and FA-80 carbs to the latest spec, if yours is already the late type it's just an overhaul kit. Includes a new HS needle, spray bar, all the gaskets/seals, and some other bits and pieces.

Bill.

Thanks again Bill.

I saw that kit but didn't realize it was for the "80" also.

I couldn't wait for later in the week so I went out to the garage last night and tried your settings and now we know why you're the expert. Moved the LS needle out to flush with the throttle lever and HS 3 1/2 out. Engine started and went past mid range, tried to die at full so I opened the HS out to about 4 - 4 1/2 and it stayed running. I'll do the final settings later as it was late and my word of advice to everyone is don't run the engine in the garage with the garage door closed[&:], Lots of smoke.


thanks for all the help

steve

bill, quick question,

how can I tell if I already have the "late type" carb?

steve

[b]Steve:

A simple answer: "Damfino."

In appearance all the parts look the same, but I've cured a few engines with the upgrade. Might be the taper of the needle, or the size of a drilling, possibly the spray bar has a slightly larger outside diameter, Could be a combination. I've really never done a close comparison.

It's easy to tell if you have the first series TN carb though, it is the one that actually uses a LS needle. Second and third series have the sleeve metering.

The first attached composite has the mid block LS needle type on the left, and the big block sleeve meter on the right. Stuck this one on to show spray bar differences, the mid block has all the fuel going out the end of the bar, the LS adjuster (needle or sleeve) occludes the end to control the flow. The big block has a slit in the spray bar, the needle or sleeve moves to restrict the size of the opening.

Second composite shows all mid block parts, sleeve type on top. Don't be misled by the choke on the needle type, the choke can be used on either. Second and third series carbs look the same; both sleeve metering.

Bill.