3K-H Carb Issue / 3K-B Information

[stefaantje]

Hi all Rolla-gurus!

 

I have a nice little 3K-H with only 70k km on it in my 1981 Starlet kp62.

Unfortunately, I'm experiencing some troubles with getting it back in running condition. (it has been sitting out in the cold for 5 years)

 

When idling, the engine always stalls. I have to keep the choke pulled out to keep it running at idle.

Any suggestions how I can find the root cause of this problem?

 

 

Apart from this, I'm looking for some info on the 3K-B engine. The block and head, are they different from my 3K-H?

Would the 3K-B inlet manifold + dual carbs fit directly on my engine? What power gain is to be expected in this case?

(and should I expect big problems with setting up the dual carbies?)

 

Thanks a lot,

 

Stefaan (from Belgium)

[coln72]

A 3k-h should have a fuel cut off soleniod on the carby. Mine did anyway. If this is not getting 12 volts when the ignition is on, it will not run properly.

 

Think the 3k-b head had bigger ports and a different cam profile. Maybe even higher compression????? That said, the manifold will bolt up to your head but will not bolt to your exhaust manifold. The bolt positions where the inlet and exhaust manifolds bolt together are usually different. To avoid this, most people run extractors.

 

Roughly you will be looking at a 10hp gain from bolting on the 3k-b carbs. With a cam, compression increase and some port matching it will be more. I never had any issues fitting up the 3k-b inlet and carbs. They were set and forget in my case. Just make sure you find a set that has all the linkages and the aircleaner as without these you need to do a bit of work to get them working.

 

Also be careful with what type of throttle cable the carbies are set up for. There are two types, and they may not suit your current set up, but this can be overcome without too much worry.

[stefaantje]

A 3k-h should have a fuel cut off soleniod on the carby. Mine did anyway. If this is not getting 12 volts when the ignition is on, it will not run properly.

 

Think the 3k-b head had bigger ports and a different cam profile. Maybe even higher compression????? That said, the manifold will bolt up to your head but will not bolt to your exhaust manifold. The bolt positions where the inlet and exhaust manifolds bolt together are usually different. To avoid this, most people run extractors.

 

Roughly you will be looking at a 10hp gain from bolting on the 3k-b carbs. With a cam, compression increase and some port matching it will be more. I never had any issues fitting up the 3k-b inlet and carbs. They were set and forget in my case. Just make sure you find a set that has all the linkages and the aircleaner as without these you need to do a bit of work to get them working.

 

Also be careful with what type of throttle cable the carbies are set up for. There are two types, and they may not suit your current set up, but this can be overcome without too much worry.

 

Thank you for the extensive reply ;)

The cut-off solenoid on the carby is working fine (well, it 'clicks' when I connect and disconnect the connector, so I guess that's ok?)

What else could be the problem?

 

Concerning the 3K-B: when using the standard 3k-b inlet manifold, I can no longer use the standard 3k-h exhaust manifold?

[tojo2]

+ might not be room for the 3kb stuff in your starlet as its LHD

 

 

Try to get a gasket kit for your carb and clean it :yes:

[parrot]

Yes, the idle circuit is probably blocked or silted up. The choke circuit circumvents the idle circuit.

 

KC & 3KC engines ran 9:1 compression, KB & 3KB 10:1 compression and different cam.

 

3KH I don't have the specs for.