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29 June 2015, 16:18
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#1
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Member
Country: UK - England
Town: Sheffield
Boat name: Touch Bottom
Make: Avon
Length: 4m +
Engine: 50 hp Merc Power t&t
Join Date: Jul 2008
Posts: 288
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4hp Yamaha, problems.
I have a 4hp 2 stroke Yamaha, circa 1985. It refuses to start, can any one tell me how to check the ignition timing on this engine please. I have re built the carb using new diaphrams and gaskets, but it still has the face on. Any help in pacifying this little sod will be appreciated.
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29 June 2015, 16:24
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#2
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Member
Country: USA
Town: S. Carolina
Boat name: D560
Make: Avon
Length: 5m +
Engine: 2016 Merc 115hp CT
Join Date: Aug 2013
Posts: 1,277
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Quote:
Originally Posted by Mercury
I have a 4hp 2 stroke Yamaha, circa 1985. It refuses to start, can any one tell me how to check the ignition timing on this engine please. I have re built the carb using new diaphrams and gaskets, but it still has the face on. Any help in pacifying this little sod will be appreciated.
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Are you getting spark?
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Richard
Gluing geek since 2007
Opinions and intepretations expressed are solely my own and do not express the views or opinions of my employer
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29 June 2015, 20:08
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#3
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Member
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 1,431
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Kill cord connected?
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30 June 2015, 07:50
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#4
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Member
Country: UK - England
Town: Sheffield
Boat name: Touch Bottom
Make: Avon
Length: 4m +
Engine: 50 hp Merc Power t&t
Join Date: Jul 2008
Posts: 288
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Quote:
Originally Posted by office888
Are you getting spark?
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Hi, Yes spark is there, but about every fourth pull or so I get a little backfire, thats why I question the timing.
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30 June 2015, 07:51
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#5
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Member
Country: UK - England
Town: Sheffield
Boat name: Touch Bottom
Make: Avon
Length: 4m +
Engine: 50 hp Merc Power t&t
Join Date: Jul 2008
Posts: 288
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Quote:
Originally Posted by paintman
Kill cord connected?
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Hi. No kill cord on this, so I checked kill button it's working fine..
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30 June 2015, 07:56
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#6
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Member
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 1,431
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If you squirt a small amount of petrol into the carb intake does it attempt to run?
Has it ever run properly in your ownership?
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01 July 2015, 01:07
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#7
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Spammer
Country: Canada
Town: Southern Ontario
Boat name: -Unknown-
Make: SeaMax
Length: 4m +
Engine: Merc/Minn Kota
Join Date: Mar 2012
Posts: 216
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after all the work..RUSH it in. Seriously. 20-40 pounds they'll set timing, start choke, ignition coils ohm tests. All kinds of stuff based on your work.
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01 July 2015, 01:41
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#8
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Member
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 1,431
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Quote:
Originally Posted by Nightfisher
after all the work..RUSH it in. Seriously. 20-40 pounds they'll set timing, start choke, ignition coils ohm tests. All kinds of stuff based on your work.
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Is this an ad for a company called RUSH in Ontario? If it is, it might be a bit far for the OP who's in England.....
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01 July 2015, 09:07
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#9
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RIBnet admin team
Country: UK - England
Town: Cambridgeshire
Boat name: Nimrod II
Make: Aerotec 380
Length: 3m +
Engine: Yam 15 Tohatsu 9.8
Join Date: Nov 2007
Posts: 8,994
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Agree it's important to know if it's ever been running for you and what has been done so that it doesn't go now.... just the carb overhaul??
Agree too a squirt of fuel down the carb should make it fire for a couple of seconds if it's a fuel issue... pull the plug and turn over to watch for spark to check if it's strong or weak.
Timing doesn't go out (usually) unless fiddled with.
Does this have electronic ign or points? Electronic is usually reliable but points can fail.... they are rarely checked on an outboard due to the hassle of removing the flywheel.
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01 July 2015, 21:52
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#10
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Member
Country: UK - England
Town: Sheffield
Boat name: Touch Bottom
Make: Avon
Length: 4m +
Engine: 50 hp Merc Power t&t
Join Date: Jul 2008
Posts: 288
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Quote:
Originally Posted by paintman
If you squirt a small amount of petrol into the carb intake does it attempt to run?
Has it ever run properly in your ownership?
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Iv'e not tried the squirt treatment yet, But it was running fine last year, had this from new btw.
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02 July 2015, 00:51
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#11
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Member
Country: UK - England
Make: Ribcraft
Length: 5m +
Engine: Yamaha
Join Date: Feb 2006
Posts: 309
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If the spark is there there is no problem with the ignition system, there are no points and timing can't be out as you cannot adjust it on the 4hp, it has a fixed timing and ignition curve.
99% of the time it is the carb at fault. Go through it again. Check jets, low speed one screws into the side of carb easy to miss if you don't know it is there. Diaphragms definatly the right way round with the little cup washer and spring in position? Spring fits into recess in fuel pump casting and cup washer fits onto spring and presses against diaphragm.
Compression? Without a compression gauge you should be able to get a good feel for it pulling it over. At 30years old the crankseals may be starting to go which does affect starting.
Far better engine than anything four stroke on the market these days.
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06 July 2015, 13:08
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#12
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Member
Country: UK - England
Town: Sheffield
Boat name: Touch Bottom
Make: Avon
Length: 4m +
Engine: 50 hp Merc Power t&t
Join Date: Jul 2008
Posts: 288
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Quote:
Originally Posted by paintman
If you squirt a small amount of petrol into the carb intake does it attempt to run?
Has it ever run properly in your ownership?
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Squirty has done the trick, so it could have been the reed valves throwing the dummy out..
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