13 replies to this topic

[Adge456]

Hi all.

I've been working on my mini for a while after it sitting for 6 years with a blown head gasket. I've got it 'running'. With the choke out, it runs ok but when it's up to temp and I take the choke off, it drops revs a lot, then picks up a bit then drops off again.
My thoughts was to increase the idle but it just surges higher then almost stalls and repeats this. I then thought maybe it's too lean, increasing revs but almost stalling due to fuel starvation? I've adjusted it slightly but don't want to carry on as I may make things worse if I follow my untrained intuition. Perhaps it's too rich and flooding? I just don't know.

Any help would be great.

It's a 998 with a HS4 carb.

[Spider]

How old is the fuel in it ?

The other thing is there's every chance the fuel system has dried gunnmy residue through it and will likely need a clean out.

[Adge456]

It's new fuel. I suppose there is a possibility that there was some old fuel in the lines but as stated, it seems to run ok with the choke out. Just not when it's at temp and choke off.
I have a glass fuel filter and the fuel seems to be clean coming in, no bits in the filter, no odd color. The float has been cleaned also.

[sonscar]

Air leak,manifold or carb gaskets possibly.Have you reconnected the vacuum pipe?Steve..

[Adge456]

The vacuum pipe is back on yes. I will check for manifold leaks. I can spray a bit of WD40 on them and see if the engine changes right?

[timmy850]

Have you got oil in the dashpot/damper?

[Adge456]

Yes, got new oil in the dash pot as even when the choke was on and idling ok (before taking the choke off and causing the main issue) when I touched the choke, I just heard a suck of air and the engine bogged. New oil sorted that

[Adge456]

Had it running today and tried spraying WD on the manifold and carb gasket area but noticed no difference.

[Adge456]

Just decided to play about with the timing which 'sorted' it. It's idling fine now which is great. However I set it using a strobe originally to 4° I believe. However now it's barely on the teeth on the largest degree side. Is this just masking a different issue? Could the pulley and chain have been put on wrong in a previous life? Is so, is this an imidiate issue?

[sonscar]

Be careful randomly adjusting timing as serious engine damage can occur quickly.Rezd how your particular engine should be set and follow the method given.Steve..

[Adge456]

Thanks again for your reply. I didn't run it long like that as I thought that it can't be healthy but thought it may give an indication. Good old AI said that it is only masking the issue and could be due to not enough fuel and the added advance could be allowing a longer time for the little fuel to burn. It also said it could still be a leak. It said to spray brake cleaner on the manifold area, I have previously used WD with no change but maybe it needs to be brake cleaner? It's been a while since I did that little test

[gazza82]

WD is a water repellent wrapped up as a lubricant (which will damage rubber if used a lot!).

Brake cleaner is a solvent and so will include burnable chemicals which will alter the idler if you have an air leak.

AI is a poor substitute for asking on a forum. Most answers are gleaned from trawling the web for typical answers .. answers which are often wrong but don't have anyone to correct or update them!

[Adge456]

I know it's not the substitute, and that's why I'm using the forum but it may help certain things in a pinch.

I did have a thought however. When I put fuel in the turn the car over originally I used E10 as it was all the local had at that time. I know it's not good but thought one can isn't going to degrade the parts and would do until I can fill the tank. I just remembered that I used E10 and wonder if the burning capability may be causing the issue? Had a little look and it can cause a lean mixture and potentially boiling.

[Adge456]

Just got 10 liters of e5 (had to drive out of town even just to get that) and it seems to be idling much better. Still has slight surge but nowhere near the revving up and almost stalling so hopefully that is the issue and just some E10 still in the line?