BVS153 barn find - fuel issue?

[DMUK21]

Hello all!

I've recently bought a house and discovered a Hayter Hunter Autodrive 41 301 collecting dust in the garden shed amongst other gifts from the previous owners.

I'm determined to bring it back to life, but while I understands the basics of an engine I'm not overly mechanical and could use some advice.

Engine is Tecumseh BVS 153, with a Dellorto FHC20 float carb. Have done the basics and replaced the spark plug and we have compression, fuel in the tank and oil but it won't fire.

If I put a drop of fuel in the cyclinder and reconnect the plug, it fires first time, revs to the sky and stops. If I put a drop of fuel in the air intake, it fires 3rd or 4th time, revs to the sky and stops.

Not sure if the high revving is a secondary issue, but it seems that the engine is able to run, and we have a problem getting fuel from the tank through the carb (pipe to carb is clear). Are there any things I can do at this stage to narrow down the issue or am I just looking at taking the carb to bits and clean and cross my fingers I can put it all together? I've attached some photos in case it helps.

Many thanks!

D

 

[Rivets]

Sounds to be like you are going to have to remove the carb and give it a good cleaning and rebuilding. I’m assuming this is a Tecumseh engine built for European use, very similar to an American model TVS. This manual may be of some help. You’ll need to figure out which carb most matches yours by viewing the pictures. If you have more questions please post back. http://www.smallenginesuppliers.com/html/engine-specs/tecumseh/Tecumseh_quick_reference.pdf

 

[DMUK21]

Thanks Rivets for the advice and manual. You are 100% correct that I am typing this from the UK. I've done some more reading and wonder if the hole in the carb that sucks the fuel up from the float is blocked/clogged so that's where I'll go. The more carb diagrams I've looked at the more I think being able to take it off, clean it and get it back on intact will be a worthwhile victory even if it doesn't start.

 

[DMUK21]

Update: I took the carb off and cleaned it, put it back together, and while it sounds MUCH better and runs for a little longer, it only does so when directly fed with fuel through the air intake or through the spark plug hole. Fuel is getting into the float bowl, just seemingly not to the cylinder. I am throughly confused.

I also noticed that the "twisty" thing that rotates the shutter on the opposite side of the air intake (throttle shutter?) when you increase the throttle lever to the choke position doesn't go back to the standard position when you decrease the throttle - the cable/spring slackens but the "twisty" thing stays where it is, unless you press it back with your finger. The choke shutter rotates back and forth normally though.

 

[Rivets]

Please look at the carbs in the manual so you can identify “the twisty thing”. This will give us a better picture of what you are talking about. Second, that screw on the side of the carb is the idle jet. Make sure the passages are open.

 

[Born2Mow]

Unlike USA carbs, your model seems to have an idle circuit as witnessed by the screw we see prominently displayed in the middle of photo #1 and 2. Engines may RUN on the main jet, but they actually start on the IDLE circuit. So you'll want to remove that screw and blow carb cleaner through that passageway. Careful when you remove the screw, there are other items in there like a spring and possibly an o-ring. Don't loose those tiny pieces.

When you re-install the screw, spring and bits, do so with a VERY light touch. When the screw bottoms-out, STOP TURNING !! Then reverse the screw outward 1 to 1.5 turns by watching the screw head. Doing so will go along way toward getting your motor running properly.

 

[Rivets]

Born2Mow, you are partially correct, that screw has passage ways in it. But after cleaning it you should fully seat it back into the carb body. Do not back it out after seating, there is no adjustment. Very similar to the idle jet and the old plastic body Lawn Boy carbs.