Flat Spot

[benren4]

Hi
I have recently bought a Spanish import R4 which I cannot get to run properly. It starts and idles ok but will only accelerate if given a bit of choke, even when fully warmed up.
I have overhauled all ignition components and have good sparks.
I have good even compression (new head gasket) and no manifold or carb mount flange leaks.
Problem has to be the carb which is a 32mm Solex. (Engine is 1108cc 688 type year 1988)
My Haynes manual is very confusing regarding identification of the carb:
a) giving data in the supplement chapter for a Type 32 SE1A,
and b) showing an exploded view diagram labelled as a Type 32 EISA-4
and c) a component location diagram labelled as a Type 32 SEIA.
Anyway when cleaning the carb. I managed to damage the air compensating jet(ref c) above) which was very tight and half of the brass head to one side of the screwdriver slot broke away. This is a big jet which I now cannot get out but I can see down inside it so know it is not blocked. It actually seems to have an internal thread so it is possible there is a part missing?
Question is could the missing part or the broken off part of the screw head make such a massive difference to to cars performance?
And if so does anyone out there have a spare carb I could buy or try?

As a new subscriber to this forum I am looking foreward to a deluge of suggestions and offers to sort out my problem!!

Ben Courage

 

[Smurfmf84]

Hi in argentina that motor came with same carb. I have info about it, but it will be in spanish. let me know if it's usefull I can easily send you the files.

BR

 

[benchseat]

Those Solex carbs are very complicated and absolute b***rds to set up correctly. Best of luck in doing so : but you may well find that even when everything is adjusted properly there will still be a flat spot when the engine is idling and you press the accelerator. You'll just have to live with this. Once you get used to it, it is easy to circumvent (e.g. by opening the choke slightly when pulling away from stationary, or carefully revving the engine before letting in the clutch). I think this model carb also has an accelerator pump and it might be worth checking the linkage to make sure it is not slack.

My 845cc R4 has the same problem. It just goes with the territory and once you are certain you have set the carb up correctly it wouldn't be worth pursuing a problem which may be ultimately insoluble. I've managed 101000 miles in that car so it can be done!

 

[benren4]

Thanks for responses guys.

Smurfmf84 I would appreciate it if you could send me the data that you have. My e-mail address is <liz.courage@talk21.com>

Benchseat---I know what you mean about living with some hesitation but as the car is it just isn't driveable!

My local scrap yard has a 32mm carb from a Peugeot 205---I might give that a try!

 

[Cornish4]

Hi Ben, welcome to the forum, and nice to see another 4 in the Westcountry. Have you checked all the rubber hoses of the emissions side of the carb? A small split there could cause a problem. I'm guessing now that the 32 has a similar set up to the slightly earlier 28, and I know on that the condition of the rubber pipes is important. Regards Brian.

 

[benren4]

Hi to you all
Am very pleased to report that car is now running reasonably well 'tho fine tuning still ongoing.
The problem was self-inflicted as it turned out. When I had taken the carb off to check it I had noticed the connection at the manifold end of the breather tube from the rocker-box seemed to be blocked. I had used a 5mm drill,just twisting it with my fingers, to clear the black carbon like deposits out of the pipe. As a result this was allowing it to suck in much too much air.
It seems that the black stuff was actually a plastic restrictor!
I was advised by Robert Doran to make a restrictor by drilling a tiny hole in the end of a tyre valve dust cap (the old metal type) as this is the perfect size to push up inside the rubber hose. With this in place I was able to get the car to run without the choke and hence go through the setting procedure with the air and fuel adjusting screws.

 

[Cornish4]

Hi Ben, I'm glad to read that you sussed out the problem, and that your 4 is now back in good health. That's a useful tip from Rob.