Is It As Bad As I Fear?
#1
Posted 15 September 2020 - 06:35 PM
Recently noticed a little smoke upon start up.
Lately getting whiff of petrol from the exhaust.
Went to take it for a spin yesterday and it would not start.
Plumes of smoke later we eventually have lift off, stinks of petrol and hesitates when you accelerate. Though will rev freely.
Pulled each HT lead to see if it was a misfire and no change to engine when cylinder 4 is removed. Changed leads and checked all plugs.
Cylinders 1&2 very sooty, cylinder 3 a little wet and black. Cylinder 4 very wet and black. I could not tell if it was oil, fuel or water.
Clearly cylinder 4 plug was fouling.
Adjusted the mixture and tried to do a compression test and something's clearly not right with my compression tester as they all show 40-45 PSI.... I'll leave that there until I can get another tester to check it. Let's just assume they are ok and the tester is a but dud.
Re-start after the basic clean up and no real change to symptoms. Plugs were still showing same signs after 10 mins Idle and the exhaust smoking and still stinking of petrol.
I'm thinking it's probably the cylinder head gasket, prehaps water in 3&4 causing no spark and unburnt fuel.
Just ordered a new gasket set.
Any other thoughts?
Thanks.
#2
Posted 15 September 2020 - 06:44 PM
I think you may it too rich, what needle is fitted and is it correct for the spec of engine?
#3
Posted 15 September 2020 - 06:47 PM
#4
Posted 15 September 2020 - 06:47 PM
Edited by robert.hedges, 15 September 2020 - 06:48 PM.
#5
Posted 15 September 2020 - 06:57 PM
#6
Posted 15 September 2020 - 06:59 PM
#7
Posted 15 September 2020 - 07:10 PM
Now I'm thinking it's the stem seals. Both failing though... fresh build? Seems wierd.
Attached Files
#8
Posted 15 September 2020 - 07:25 PM
Before going to a lot of trouble I would try having a look at the needle jet and float in the carburettor that feeds cylinder 3 and 4.
#9
Posted 15 September 2020 - 07:27 PM
#10
Posted 15 September 2020 - 08:14 PM
Before going to a lot of trouble I would try having a look at the needle jet and float in the carburettor that feeds cylinder 3 and 4.
Almost certainly this will be the issue, the float valve isn't shutting off and raw fuel is just pouring in to it.
#11
Posted 15 September 2020 - 08:24 PM
Feel a lot more confident in the collective diagnosis.
I'll start at the easy stuff like checking the carb first. All too easy to start researching thinking the worst
#12
Posted 16 September 2020 - 06:32 AM
#13
Posted 16 September 2020 - 10:26 AM
Check the jets are not sticking on the jet bearings, it can happen.
Otherwise as Moke says, the float valves can be stuck open, and flooding the carbs, hence a big smell of petrol and plumes of smoke
#14
Posted 20 September 2020 - 02:57 PM
I'm guessing this was the route cause of the issue?
Yet to get the single carb up and running.
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