Hello everyone,
Iam having a problem of uneven running on my singer gazelle vi 1725cc which struggles to stay running in town driving and hard to re-start when hot. Also slight petrol/ exhaust smells when driving but not overpowering and obvious leaks. The plugs look the right colour when inspected. Starts from cold easily and ticks over nicely. I have done a compression test and results are from the rad 75, 53, 69 and 57 I put some oil down the bores and these improved 82, 75, 88 and 80 these all seem low to me. So 2 questions, what should be good condition engine psi and secondly, any idea what my problems are. Any help would be much appreciated. Regards giles
Compression test psi
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rhythmrider
- Posts: 89
- Joined: Mon Sep 02, 2013 6:58 pm
Re: Compression test psi
One cause of low numbers in a compression test is that all of the sparking plugs should be out of the engine during the test.
And or course a worn out starter motor.
Sometimes hard starting when hot is caused by problems with the starter motor bushings tightening up when hot.
If you have ruled out everything else, these things might be worth looking into.
If you think you might have a lot of "blow-by" remove the oil filler cap and look inside.
if you see a yellow substance like warm butter on the inside walls of the filler neck, you have a lot of blow-by.
And or course a worn out starter motor.
Sometimes hard starting when hot is caused by problems with the starter motor bushings tightening up when hot.
If you have ruled out everything else, these things might be worth looking into.
If you think you might have a lot of "blow-by" remove the oil filler cap and look inside.
if you see a yellow substance like warm butter on the inside walls of the filler neck, you have a lot of blow-by.