holden 355 back firing off idle

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bauchy
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Joined: 11 Mar 2009, 20:34

holden 355 back firing off idle

Postby bauchy » 26 Mar 2012, 21:13

hey guys, hopeing someone can diagnose the problem ive got. had my boat out with stroker holden abit, been running fine but yesterday it started back firing off idle. need to feather the throttle to keep it running. once its moving it gets to around 3000 rpm then it starts popping and hesitating. it does this untill about 3500rpm, also when turning it keeps dieing. im more then confident the ignition is fine because it hasnt been touched since last time it was running. the engine is running an ice ignition setup and hasnt been changed since first starting it.

am i right that there is a fuel problem?? the carby is a holley 750 dp which has been fine untill now. the engine makes 530hp so the engine is not over fueled. im thinking it may have poo in it or the floats arnt high enough etc???

any ideas???

brian

Alan
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Joined: 04 Mar 2009, 22:24

Re: holden 355 back firing off idle

Postby Alan » 27 Mar 2012, 00:11

Brian,
sounds like fuel, float levels rarely change that fast, check for poo, pull it apart make sure the progression ports are all clear.
Alan.

bauchy
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Joined: 11 Mar 2009, 20:34

Re: holden 355 back firing off idle

Postby bauchy » 29 Mar 2012, 09:41

Thanks alan. Checked everything and still no better. Ripped dizzy out and the lil cog on the bottom was shagged. Dunno why or how but its got a new one and all is sweet again. Test run again saturday arvo and see how it goes. Brian

Alan
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Joined: 04 Mar 2009, 22:24

Re: holden 355 back firing off idle

Postby Alan » 29 Mar 2012, 19:11

Brian, I assume this thing has a roller cam, so you need to make sure the gear is suitable for a steel cam or it will do it again. The other issue is that the oil pump drive gear must also be suitable, you need to talk with the engine builder to confirm that he put the right one in other wise you'll run the risk of loosing the oil pump drive.
Alan.

bauchy
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Joined: 11 Mar 2009, 20:34

Re: holden 355 back firing off idle

Postby bauchy » 29 Mar 2012, 22:54

hey alan, just a solid cam in this engine, my other 355 has a roller cam. i rang the guy i got the ignition off and he said the gear i was provided with was not correct. another one is in the post but its the same as the one thats now in the motor so all should be good.

when we got it sorted again last night i was very happy to hear it. snappy and revving like it should. i cant wait to get some hours on it over the weekend then again over easter up the river. fingers crossed there isnt to much poo floating in it by then.

isnt it frustrating how you can be making good progress and something like this just ruins the motivation

brian

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hookster
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Re: holden 355 back firing off idle

Postby hookster » 31 Mar 2012, 09:10

The lake's been flat as a tack lately Bauchy, I'm taking mine out this evening

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Greg
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Re: holden 355 back firing off idle

Postby Greg » 31 Mar 2012, 14:34

I went out on Eppalock this morning - it was rubbish! Typical Eppalock slop.

bauchy
Posts: 535
Joined: 11 Mar 2009, 20:34

Re: holden 355 back firing off idle

Postby bauchy » 31 Mar 2012, 21:39

hooky i been out all arvo, testing, changing and revving hahaha love it. got kicked off my favourite lake because boats to loud apparently, told weir keeper he must be to old :P

got me old woody up to 68mph at 5200rpm this arvo so making progress now .


greg , i was looking at going to eppalock late this arvo greg but knew deep down it would be sloppy. just how it is usually. every time ive been its been less then average which isnt good for testing and getting a boat to go.


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