Engine: 140 1986cc B20A: - Ignition Timing Details please.

scimitar · Jul 21st, 2013, 21:24

I am not sure exactly which B20 Engine I have, it is fitted in a boat. However having fitted electronic ignition and using unleaded petrol I wish to accurately reset the ignition timing. Please can anyone supply the information please. Many thanks in advance.

arcturus · Jul 22nd, 2013, 09:20

This thread may help
http://www.volvoforums.org.uk/showthread.php?t=183601

swedishandgerman · Jul 22nd, 2013, 12:51

B20 engines for boats had different distributors to those fitted in cars. That is unless you have a car engine in your boat!

Please could you provide details of the last three numbers of the part number on the side of the distributor body? If it ends in 078 or 077, then it's a car distributor and you should set the timing at 34 degrees at 2,750 rpm

scimitar · Jul 22nd, 2013, 16:36

Thank you for your replies. The Carb as fitted is a Solex 44PA1 downdraft and the distributor uses bob weights for advance and retard. There is no vacumn advance and retard. I will have to re-visit the boat this coming weekend to get the distributor numbers. Will come back with details then.

scimitar · Aug 11th, 2013, 21:24

The distributor on my engine is a Bosch with a plate numbered :- 0231153012. Anticlockwise rotation and has centrifugal bob weights. Best ignition timing that I can find by swinging the distributor and adjusting the Carb is 10 degrees BTDC. Any comments please.

scimitar · Aug 11th, 2013, 21:34

The distributor on my engine is a Bosch with a plate numbered :- 0231153012. Anticlockwise rotation and has centrifugal bob weights. Best ignition timing that I can find by swinging the distributor and adjusting the Carb is 10 degrees BTDC. Any comments please.

Derek UK · Aug 12th, 2013, 10:59

10º will probably be OK but 8º might be better when using normal unleaded rather than premium fuel. What rpm do you usually cruise it at, if you have a rev counter?

scimitar · Aug 12th, 2013, 23:27

Hello there. Cruising speed of 4 knots, on River Avon, is 2000 rpm. Both engine revs and speed are shown on seperate dials. So normally maximum engine revs might get up to 2500 rpm if going against a fast current. Yesterday spent a lot of time setting timing and changing carb over but had difficulty in getting mixture set correctly because, I think that at an idling speed of 1000rpm fuel was being pulled through the carb's main jet. Will recheck at 750-800rpm and see if the mixture screw has any effect. Reason for not too low an idling speed is that when engaging forward or reverse at this speed the engine must not stall as drive is engaged. Thank you for all your help.

Jul 21st, 2013, 21:24	#1
scimitar Scimitar Last Online: Aug 20th, 2017 13:45 Join Date: Dec 2003 Location: Solihull	Ignition Timing Details please. I am not sure exactly which B20 Engine I have, it is fitted in a boat. However having fitted electronic ignition and using unleaded petrol I wish to accurately reset the ignition timing. Please can anyone supply the information please. Many thanks in advance.

Jul 22nd, 2013, 09:20	#2
arcturus arcturus Last Online: Today 08:14 Join Date: Mar 2006 Location: Sagres Portugal	This thread may help http://www.volvoforums.org.uk/showthread.php?t=183601 __________________ life's too short to drink bad wine

Jul 22nd, 2013, 12:51	#3
swedishandgerman Premier Member Last Online: Oct 23rd, 2023 21:39 Join Date: Apr 2007 Location: EXETER	B20 engines for boats had different distributors to those fitted in cars. That is unless you have a car engine in your boat! Please could you provide details of the last three numbers of the part number on the side of the distributor body? If it ends in 078 or 077, then it's a car distributor and you should set the timing at 34 degrees at 2,750 rpm __________________ 2006 XC70 D5 Manual 1968 Amazon Estate, B18A + Overdrive 2019 V60 D3 Momentum Pro Manual 1970 Amazon 2-Door 1970 142DL

Jul 22nd, 2013, 16:36	#4
scimitar Scimitar Last Online: Aug 20th, 2017 13:45 Join Date: Dec 2003 Location: Solihull	Timing Details for B20 Engine. Thank you for your replies. The Carb as fitted is a Solex 44PA1 downdraft and the distributor uses bob weights for advance and retard. There is no vacumn advance and retard. I will have to re-visit the boat this coming weekend to get the distributor numbers. Will come back with details then.

Aug 11th, 2013, 21:24	#5
scimitar Scimitar Last Online: Aug 20th, 2017 13:45 Join Date: Dec 2003 Location: Solihull	B20 Timing Details, The distributor on my engine is a Bosch with a plate numbered :- 0231153012. Anticlockwise rotation and has centrifugal bob weights. Best ignition timing that I can find by swinging the distributor and adjusting the Carb is 10 degrees BTDC. Any comments please.

Aug 11th, 2013, 21:34	#6
scimitar Scimitar Last Online: Aug 20th, 2017 13:45 Join Date: Dec 2003 Location: Solihull	B20 Timing Details, The distributor on my engine is a Bosch with a plate numbered :- 0231153012. Anticlockwise rotation and has centrifugal bob weights. Best ignition timing that I can find by swinging the distributor and adjusting the Carb is 10 degrees BTDC. Any comments please.

Aug 12th, 2013, 10:59	#7
Derek UK VOC Member Last Online: Today 16:54 Join Date: Jul 2006 Location: Chatham	10º will probably be OK but 8º might be better when using normal unleaded rather than premium fuel. What rpm do you usually cruise it at, if you have a rev counter?

Aug 12th, 2013, 23:27	#8
scimitar Scimitar Last Online: Aug 20th, 2017 13:45 Join Date: Dec 2003 Location: Solihull	Timing Details for B20 Engine. Hello there. Cruising speed of 4 knots, on River Avon, is 2000 rpm. Both engine revs and speed are shown on seperate dials. So normally maximum engine revs might get up to 2500 rpm if going against a fast current. Yesterday spent a lot of time setting timing and changing carb over but had difficulty in getting mixture set correctly because, I think that at an idling speed of 1000rpm fuel was being pulled through the carb's main jet. Will recheck at 750-800rpm and see if the mixture screw has any effect. Reason for not too low an idling speed is that when engaging forward or reverse at this speed the engine must not stall as drive is engaged. Thank you for all your help.

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