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Post by dpress on Nov 9, 2020 12:18:51 GMT -5
I have just finished refreshing a 330 that was an eBay purchase, and had clearly not run for a long time. It has been dismantled, cleaned and had new fuel lines, carb boot and the Zama carb has been rebuilt with the correct RB3 kit. I did not split the engine as the bore looks perfect and the piston is unworn and with no carbon staining - reed valves all excellent etc.
The issue I have is that when starting from cold the machine will always flood. The procedure I use is as per the owners book, full choke, throttle lock on and then pull start until the engine pops. Then go to half choke and keep pulling. So far it has always failed to start - the machine pops after about 4 pulls as I would expect, but by then is flooded and when I keep pulling it over it won't fire (with or without choke) and you will eventually get fuel mix being blown out of the exhaust.
It will start and run well, but only if I remove and clean the plug after the engine has 'popped', and then it will start on half choke, and run and rev well, and settles down to a good tick over. The transition between Lo and Hi seems okay as well, although it will need setting up properly when I get it cutting and fully warmed up.
I have examined the carb again today, and set the metering lever a little lower than it should be in an attempt to cure the problem but with no luck.
I have not worked on a Zama carb before - my other Homelites and Stihl machines have Walbro, so I wonder if I am doing something wrong?
Once it has started and run, I have found the machine will restart when warm first pull with no issues, so I am at a loss to explain whey it should flood when cold.
The saw is stored in my garage, and I usually crack open the fuel cap to ensure there is no fuel forced under pressure into the engine if it gets warm while sitting (I do that on all my saws).
Any suggestions would be gratefully received.
Steve
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Post by undee70ss on Nov 9, 2020 13:12:57 GMT -5
Pressure test the carburetor. Most likely needle is leaking causing the flooding.
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Post by dpress on Nov 9, 2020 13:28:13 GMT -5
Unfortunately I don't have a pressure tester, something I really should invest in if I can find one at a sensible price. I did fit all new internals to the carb - gaskets, diaphragms, and new needle valve, metering lever and spring. I had thought that if it was a needle leaking I would have flooding on all starts, hot and cold?
Steve
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Post by sweepleader on Nov 9, 2020 21:09:02 GMT -5
You don't mention if you changed the plug, but that it will start if you clean the plug. That would send me to the sparkplug store.
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Post by onlyhomelites on Nov 9, 2020 21:20:07 GMT -5
You are right; typically a leaking needle is more obvious warm than cold. What is the L needle set to? it should be between 1 to 1 1/2 turns open. If it's significantly more than that, it could explain the flooding.
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Post by dpress on Nov 10, 2020 11:56:19 GMT -5
When I mentioned cleaning the plug, what I perhaps should have said is drying it, as it gets saturated with petrol. Although not new, it is the correct Champion type and in good condition. It gives a lovely blue spark outside the cylinder. I will experiment with an alternative one.
At present the carb is set with the L needle at just under 1 1/4 turns out, and the H at 1 turn out, although as I said further tuning will be needed. It just seems weird that the only flooding issue I have is on first cold start with nothing thereafter. It almost seems as if somehow the carb is being pressurised pushing excess fuel into the engine initially before the first start. It would be easier in some ways if the carb was flooding all the time!
Steve
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Post by dpress on Nov 18, 2020 12:30:28 GMT -5
Just to update this thread. I have stripped the carb again and can find nothing amiss, lever at the correct height etc. A new spark plug has been fitted of the correct type. 5 pulls with the choke full on to make it pop, and yes, it flooded again.... This was with the Lo needle set at just 3/4 turn out - after drying the plug and starting the saw it would not run at low speed with the Lo set at that value so I had to take it to 1 turn out (the usual setting), at which it ran perfectly, idled and restarted a number of times first pull.
I still have no pressure tester, but while assembling the carb for the last time hooked up a piece of tube and blew through it, and the metering valve is clearly working fine as I could get air to pass and stop by operating the lever with my finger. With the diaphragm and cover in place there is no air leak - no air flows blowing down the tube.
So I am officially stumped and the saw has gone back under the bench for a while!
As a final thought when running the saw with the air filter cover off, as you accelerate there is a surprising plume of fuel that jets out of the main nozzle - it seems quite a lot to me, and I just wonder if the main nozzle could be flowing fuel during start up like that? I just can't work out how so much fuel is getting into the engine, sufficient to completely wet the plug after just 5 pulls on a totally empty carb that had just been stripped.
Steve
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Post by lesorubcheek on Nov 18, 2020 13:12:25 GMT -5
It seems like there was a TSB on 330s talking about a weep hole in the crankcase. I looked and couldn't find it, but maybe somebody can remember and locate it. I don't remember details, but seems like it dealt with puddling fuel. The only thing I remember for sure was thinking what a cluge it was. Anyway, maybe that'll provide something to at least try.
Dan
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Post by undee70ss on Nov 18, 2020 13:22:00 GMT -5
It seems like there was a TSB on 330s talking about a weep hole in the crankcase. I looked and couldn't find it, but maybe somebody can remember and locate it. I don't remember details, but seems like it dealt with puddling fuel. The only thing I remember for sure was thinking what a cluge it was. Anyway, maybe that'll provide something to at least try. Dan Yes, correct. |
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Post by dpress on Nov 18, 2020 14:50:24 GMT -5
Many thanks for the interesting reply. It has thrown up 2 points, mentioned in the relevant TSB which I quickly found on Leon's site, 181-014 of 1981.
First off this TSB indicates that the correct spark plug is actually a Champion DJ-7Y, and not the DJ-6J as per the owners manual. So I need to buy another plug - the DJ-7Y is a protruding nose type. Secondly it mentions the small 0.040" dia hole 'just under the reed valve'. I will need to check this just to satisfy my curiosity so that will mean taking it all apart again. Never mind....!! I will try the different spec plug first though, and see if there is any difference. If anyone has comments on what grade/type of plug you use in a 330 I would be interested to hear.
Thanks again.
Steve
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Post by blythkd on Nov 18, 2020 20:24:21 GMT -5
The weep hole is in the square transition area below the reed valve assembly. It's in one of the lower front corners, although I can't say for sure if it's toward the flywheel side or drive side. I'm thinking it's on the flywheel side. You'd miss it if you didn't know it was there. I'm just not making sense of it causing your problem. It was put there to allow any puddling in that intake area to drain out, which would avert flooding. I just can't imagine why it would fire once then need the weep hole to drain out puddling to avoid flooding. I guess for good measure you should make sure the hole is clear but it takes some doing to get there.
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Post by dpress on Nov 19, 2020 12:07:49 GMT -5
Thanks for that extra info. I will pull it apart (again) at the weekend.
Steve
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Post by sweepleader on Nov 19, 2020 17:40:58 GMT -5
As you mentioned in your first post, I often get flooding when I set the choke and pull to the first pop. I did not realize that you mentioned leaving the choke set half way when I read it the first time. In my case, I take the choke off after the first pop and pull till it fires, usually about 2 pulls. Sometimes I have to add some choke back to keep it going, this would be with SXL's, I do not have a 330.
Have you tried that, choke, pull, pop, choke off, pull? I know you have pulled a lot but if the mixture was right for the first pop, then too rich, I have always felt that the mixture had to get right again some time later with pulling lean/fresh air through to clear out the flooding.
Another question comes to mind, have you tried starting it cold without the choke? Will it pop once then? That would really indicate flooding. Maybe you have it figured out by now, hopefully.
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Post by dpress on Nov 21, 2020 12:23:05 GMT -5
Sweepleader thanks for the comment, which got me thinking. I tried the saw again today, this time without using any choke. Throttle lock on, pulled for 9 times, nothing so took the plug out which was still dry. Plug back in, choke full on pulled twice for a pop, choke full off and kept pulling until it started - about another 4 pulls. So that had the saw running, and I let it warm up thoroughly. Hot restart was a first pull affair as always.
Second time I tried starting it from cold again I flooded it, but didn't remove the plug - just took the choke full off and kept pulling to purge the fuel out of the cylinder until after about another 10 pulls it coughed into life. So maybe that is what I will have to do - just keep pulling until it starts! I do wonder if as the saw dies after the ignition is cut, whether I am getting fuel pooling below the reed valves (and not draining away), which is then drawn into the engine on the next cold start. Anyway, at least it seems I can get it started without having to remove and dry the plug every time - just keep pulling!
Mind you this saw is toying with me - the oiler has stopped working now, so I have that apart at the moment....
I am going to take the saw to work where I am in the great outdoors and test it there - my neighbours will be after my scalp if I keep going with it at home! Boy it is loud this one.
Steve
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Post by dpress on Nov 22, 2020 15:28:20 GMT -5
Just to finalise this thread - I think I have sorted it. After the comment from Sweepleader and reading all the 330 topics I could, I decided that my flooding might be partially operator error. So today I took another starting approach. Throttle lock on, choke full on, 2 pulls, choke full off, keep pulling and it starts. Hooray!! No evidence of flooding (nothing blowing out the silencer) and running really well, revs like hell. Was still definitely rich when it first caught though with a big puff of smoke, and that is running 50:1 Stihl mix.
I had the oiler apart last night, and could see no issues, so reassembled with oil in the right places to prime it. It must have taken fully 5 minutes for it to work today, including holding the saw at high revs for quite a while before a few air bubbles, and then a good strong flow of oil arrived. I can only assume I did not give it enough of a chance to prime itself when running before, but even so it seemed like an eternity in comparison to the similar pump on my 240.
In conclusion I suspect that excess fuel on start up may be a 'feature' of the design of the saw with the vertical downdraft carb, and also may be worse with the Zama make carb. Now I just need to put a couple of tanks of fuel through it to make sure the carb settings are spot on, but it is good to go.
Thanks for all the contributions.
Steve
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Post by frizzen on Dec 16, 2020 13:36:24 GMT -5
My 330 cold start seems to like: throttle lock, about 1/2 choke, pull to cough, no choke, pull and running.
I'm also running 40:1 (no EtOH) "true fuel", chopped lawnmower foam airfilter, new foam airbox seal, and whatever sparkplug was in it that's older than i am.
I came here from a much newer Husqvarna and using a throttle lock took some getting used to vs the single 'Choke, High idle, Off' thumb lever.
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