spark plugs
12 April 2006, 11:35 PM
#1
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spark plugs
Whats the difference in lettering on spark plugs. My boat outboard has currently NGK B9HS plugs in it. We are heading away tomorrow for a week of blatting about and I want to take a spare set of plugs. The nearest I can find are B9ES. As far as I can tell, the reach is the same, but does anyone know the difference between E and H type?
12 April 2006, 11:55 PM
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I've just had a look through the cross reference on www.spark-plugs.co.uk and the two types you mention deffo aren't compatible. 
13 April 2006, 12:06 AM
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Cheers Bob
- looks a bit more complex than I imagined. I thought the letter was related to running temp. Based on the chart above - the closest match would be a B8HS? I can get these OK, but would the difference in running temp have any ill effects? Don't mind if it kills the plugs quickly, but would prefer it not to kill the engine
- looks a bit more complex than I imagined. I thought the letter was related to running temp. Based on the chart above - the closest match would be a B8HS? I can get these OK, but would the difference in running temp have any ill effects? Don't mind if it kills the plugs quickly, but would prefer it not to kill the engine
13 April 2006, 12:20 AM
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I'm not sure really, I've only ever changed like for like. I should think your most likely safer going colder rather than hotter, so yeah, B8HS if you can't get 9s
13 April 2006, 12:24 AM
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9s are ordered for next week, but seem a bit of a rarity, so the 8's only need to do me for maybe 12 hours running. what do you reckon the chances of the engine running like a dog on the wrong spec are?
13 April 2006, 12:47 AM
#7
I take it it's a two stroke outboard?
Generally you can swap heat ranges based on useage needs.
If its pootling up the river, you'd want a hotter plug to stop it fouling up with oil. But for flat out blasts you could overheat it, so go for a colder rating.
As long as the fueling and oil injection is set right you shouldn't have a problem going one up or down in the heat range. Worst case is you melt or scuff a piston by getting it too hot (not that I want to worry you
)
Generally you can swap heat ranges based on useage needs.
If its pootling up the river, you'd want a hotter plug to stop it fouling up with oil. But for flat out blasts you could overheat it, so go for a colder rating.
As long as the fueling and oil injection is set right you shouldn't have a problem going one up or down in the heat range. Worst case is you melt or scuff a piston by getting it too hot (not that I want to worry you
)
Last edited by ALi-B; 13 April 2006 at 12:52 AM.
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13 April 2006, 12:55 AM
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yep - its a two stroke - mostly be flat out, with some flat out and leaning over to make it corner quicker and get the passengers off the banana and the do-nut........
Haven't quite got a grasp on this. Is going from a 9 to an 8 likely to make the engine run hotter or cooler? Is it likely to damage the engine. I can get B9HS's in the morning about 50 miles in the wrong direction, or B8HS's about 200 yards away. Do you reckon I should give up 3 hours to get the proper ones?
Haven't quite got a grasp on this. Is going from a 9 to an 8 likely to make the engine run hotter or cooler? Is it likely to damage the engine. I can get B9HS's in the morning about 50 miles in the wrong direction, or B8HS's about 200 yards away. Do you reckon I should give up 3 hours to get the proper ones?
13 April 2006, 01:02 AM
#9
This should help: http://www.ngksparkplugs.com/techinf...000&country=US
In a nutshell, a spark plug needs to work at a certain temperature. Too cold it fouls up. Too hot, it overheats and can cause detonation (and thus - if really bad, it'll start melting stuff).
Yes the the engine will run and probably will be ok on them. But I can't give a definite yes or no answer if they'll be ok for long flat-out blasts.
In a nutshell, a spark plug needs to work at a certain temperature. Too cold it fouls up. Too hot, it overheats and can cause detonation (and thus - if really bad, it'll start melting stuff).
Yes the the engine will run and probably will be ok on them. But I can't give a definite yes or no answer if they'll be ok for long flat-out blasts.
13 April 2006, 01:15 AM
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cheers bigears
That explains a lot, but now I know I know less about plugs than I thought I knew if you know what I mean.
Looks like a 3 hour trip for 4 quids worth of plugs in the morning
That explains a lot, but now I know I know less about plugs than I thought I knew if you know what I mean.
Looks like a 3 hour trip for 4 quids worth of plugs in the morning
13 April 2006, 01:26 AM
#12
Yeah, sorry about that.
I've played with temperature ratings on my 2 stoke bikes, and I'm always reminded by storys from avid 2 stroke nutters melting and seizing stuff on their modded engines due to silly things like running a little lean with stock plugs on a modded engine.
So I can't say it'll be ok knowing there is an element of risk.
Chances are it'll be ok running a hotter plug, but I don't want to get any blame if it turns out that its not. (yeah I'm coward
)
I've played with temperature ratings on my 2 stoke bikes, and I'm always reminded by storys from avid 2 stroke nutters melting and seizing stuff on their modded engines due to silly things like running a little lean with stock plugs on a modded engine.
So I can't say it'll be ok knowing there is an element of risk.
Chances are it'll be ok running a hotter plug, but I don't want to get any blame if it turns out that its not. (yeah I'm coward
)
13 April 2006, 01:34 AM
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Hi TH - Would you like to kiss my footprints.... again
BTW - Bob and Ali - Thanks a mil. It seems I have avoided potentially feking the engine up entirely. Next time you are over I take you a scoot on the nana
DW - Try and keep up
(thanks for your best efforts anyway 
)
BTW - Bob and Ali - Thanks a mil. It seems I have avoided potentially feking the engine up entirely. Next time you are over I take you a scoot on the nana
DW - Try and keep up
(thanks for your best efforts anyway )
13 April 2006, 01:43 AM
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Originally Posted by fast bloke
Hi TH - Would you like to kiss my footprints.... again
Sort it out,eh!
( I will leave this thread now or,you will blame me for muppetising it)
13 April 2006, 01:46 AM
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muppet away - the question has been answered. Next appointemnt with the doc will be 2038, most likely for chest pain or liver failure - (not joking btw - that is how long it takes to see him )
)
- without thinking about going to the doc and stopping at all the docks; driving everyone insane
13 April 2006, 01:56 AM
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sail.... thats for big girls pink lacey blouses. I think the thing that I do mostly in my boat is.....
hmmm.....
looking for a word here...........
maybe.............................
pose?
hmmm.....
looking for a word here...........
maybe.............................
pose?
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