Leeder 710 5.7L stern-drive threads please

Hi Guys its a 31 degree Winter's day here in Karratha.

I'm a Newbie to posting so please accept my apology in advance, searched the forum's but got weird results - like my search item inserted in all random posts?

Just picked up a Leeder 710 Deluxe '96 model Carby 5.7L Alpha One leg.

Can you tag me in existing site posts that discuss solutions to:

1. Mystery electrical fault that sees the engine running fine then (550 genuine hrs) stop randomly but will restart almost straight away?

1b. Service intervals must do vs can do.

2. Leeder specific prop/pitch/blade# thread for the Alpha One leg.

3. Leeder tips and tricks for weekly running.

 

Thanks guys much appreciated.

 

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 Pilbara WA


freo fatboy's picture

Posts: 17

Date Joined: 16/10/11

Mercruiser 5.7L knocking/Pinging/detonation Probs continue.

Sat, 2014-12-27 08:22

 Hi Guys

Had one pm reply to this thread (thx B&T) and am hoping someone may have found the answer to my issue number 1 above as all the others are sorted.

 

Update:  Have had a marine mechanic working on this #1 issue for the last 4 months on and off and still experiencing totally random breakdowns where the chev 5.7litre sounds like its pinging/detonating and engine won't stop when the ignition key is turned off.  Several backfires and shudders later after it finally stops it will start fine and keep going faultlessly.  Some trips it does it others not at all.  All different throttle settings and fuel levels and seas.

 

So far the mechanic (top bloke) has replaced with genuine mercruiser parts ~$1500 incl labor:

 

Ignition Coil

Knock sensor

Knock sensor module

Dizzy cap and rotor kit and sensor

SS Marine spark plugs

Ignition key switch assembly

tuning and timing etc

He doesn't seem to think it is the electrnic ignition module (thunderbolt), but says we should replace that next ($800 + labor):)

Cheers heaps for any leads or past experiences at all.

 

James - Dampier

 

 

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 Pilbara WA

Posts: 539

Date Joined: 29/03/10

 HI Google " carbon build-up

Sat, 2014-12-27 09:06

 HI 

Google " carbon build-up engine run on". Then google "decarbonising spray"

might not be the problem but have a good read.....let us know what you think

 

Cheers

freo fatboy's picture

Posts: 17

Date Joined: 16/10/11

Power Tune de carbonising spray

Sat, 2014-12-27 21:04

 Thx for the hint ccc, much appreciated.

Read up on those topics and among many other things it can sound like carbon build up causing detonation, but I ain't no mechanic.

Seems punters on youtube etc are very supportive of decarbonising outboard motors, watching all the black smoke and bits pour out of the exhaust after Quicksilver POWERTUNE foam etc is applied indicates its doing something?

One negative thing a few punters mentioned was that the carbon may be helping the worn engine seals and freeing it up may reduce compression and such, but most claim more benefits than not.  

The mechanic did get me to put a bottle of Quicksilver QUICK CLEAN in the fuel 95 ulp which seemed to make it idle better.  But the engine has broken down twice since as described previously.

Tempted now to run a can of POWERTUNE through the carby and see how she goes after.  

 

Thx again, what are your thoughts on decarbonising?

 

James

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 Pilbara WA

carnarvonite's picture

Posts: 8622

Date Joined: 24/07/07

Gear shift cut out

Sat, 2014-12-27 14:03

Check that its not the cut out that momentary cuts the spark when you shift in and out of gear, it could be set too fine and any bump will cut the power.

freo fatboy's picture

Posts: 17

Date Joined: 16/10/11

Momentary cut out blues.

Sat, 2014-12-27 21:12

 Thx for the reply Canarvonite.  

 

Sometimes when we change out of fwd or reverse into nuetral (sharply) the motor stops dead, if we change gear slowly it doesn't happen, so annoying when that ignition warning buzzer starts bleating grrrr.

Always wondered why? Thx for clearing that up.  

But when the motor breaksdown (as described above) it runs on like a car motor that has its ignition timing way to advanced, pinging and detonatiing, back firing until it wheezes to a stop, turning off the ignition key doesn't stop the motor and as there is no clutch to let out and stall it, the pinging, and run on just goes until it stops.

Could it be the momentary cut out contributing to that?

 

Ha feels like I'm talking behind my mechanic's back.

 

Thx again Canarvonite.

 

 

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 Pilbara WA

carnarvonite's picture

Posts: 8622

Date Joined: 24/07/07

Coughing and fart

Sat, 2014-12-27 21:33

With it coughing and farting but continuing to run with the key turned off sounds like carbon build up creating extra compression and making the fuel to precombust and keep the engine running of sorts.

Never tried any of those additives or sprays but they could save you having to pull the heads off to de coke it.

freo fatboy's picture

Posts: 17

Date Joined: 16/10/11

PowerTune it is then

Sun, 2014-12-28 11:59

 Thx Canarvonite, looks like a can of PowerTune is on the shopping list in the next few weeks.  Will let you know how it goes.

 

Cheers James

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 Pilbara WA

z00m's picture

Posts: 1086

Date Joined: 10/05/14

 Check the fuel tank

Sat, 2014-12-27 17:08

 Check the fuel tank breather. A test is the run with the fuel cap loosened (make sure it is attached to something in case it loosens itself all the way!!) may show it being starved of fuel. When the boat stops the pressure is equalised again and off you go.

 

freo fatboy's picture

Posts: 17

Date Joined: 16/10/11

Now that you mention it?

Sat, 2014-12-27 21:29

 

Thanks for the hint zOOm, it rang a bell.

Its never broken down as described above when the fuel tank has been topped right up.

When we fill up at the servo fuel jets out of the vent when it reaches capacity - does this mean it is clear of blockage?  The cap is an old solid brass chrome plated screw on type job with no rubber seal inside, scared I'll lose it over the side as it doesn't have a safety chain etc.

Last time it broke down 2 weeks ago we had half a tank left, were in a pig of a side on rolling 2m sea (very spew worthy) coming out of flying foam passage and were doing 1200rpm and about 5kts.  Have been out twice since then on topped up tank (carried spare fuel and refuelled on Rosemary Island) both 20km runs out and back over two days and motor ran faultlessly.  After a breakdown, to start it again involves probably 10 cranks when normally 2-3 will start it, is that a sign its empty of fuel in the line I wonder?

Two other times I remember it breaking down were in not so bad rolling seas but not calm either and half to quarter full tank.  Maybe there is a connection?

Could it be the old mechanical fuel pump needing rebuilding?  Or adding an electric pump?

I'll have to ask the mechanic cause I don't really know how to check it out more.

 

Thanks again zOOm, much appreciated.

 

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 Pilbara WA

glastronomic's picture

Posts: 892

Date Joined: 16/02/11

If your engine has a

Sat, 2014-12-27 22:55

If your engine has a mercruiser "submersible" fuel pump, the one where the fuel cools the electric motor then there might lie a or the problem.
You might have a small air leak in your fuel line and it lets the fuel escape so to speak.
These "useless' mercruiser pumps cannot self prime and have great difficulty getting rid of air in the fuel line!
when operating dryish, they "melt the windings/bearings"
To fix this; install a proper primer fuel pump (and good filter/water separator) of the correct pressure in front of it plus a return fuel line back to the tank, to get rid of air.

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freo fatboy's picture

Posts: 17

Date Joined: 16/10/11

Thanks Glastronomic

Sun, 2014-12-28 11:57

 Cheers for that Glastronomic.

I can see a big mechanical fuel pump mounted on the rhs of the engine but have no idea if it has a submersible pump as you describe, how do you tell on these carby 350 chev models?

The mechanic should be able to tell me I suppose, the floor of the boat has an inspection port for both the fuel shut off valve and another for fuel guage sender, but other than that the 180litre tank is fully enclosed (unaccessible) under floor.

Thanks again, much appreciated.

 

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 Pilbara WA

glastronomic's picture

Posts: 892

Date Joined: 16/02/11

Mercruiser "submersible"

Sun, 2014-12-28 12:40

Mercruiser "submersible" pumps are mainly on the Fuel injected models.
If yours is one with a rocker arm mechanical pump action then my post is of no use to you!

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Posts: 71

Date Joined: 20/01/14

Re running on

Sun, 2014-12-28 14:22

Have a look for a fuel shut off soliniod on the carby, I have a Toyota forklift that runs on as you describe, and the fuel shutoff not working seems to be the issue with it.

freo fatboy's picture

Posts: 17

Date Joined: 16/10/11

Problem Solved - Finally.

Fri, 2015-06-05 07:03

 Good news

 

My mechanic ordered a new ignition control module based upon further research he completed after we changed the knock sensor out.

 

The tiny post it note sized thunderbolt 5 ignition module came out and a new mercruiser upgraded nippon denso ignition module went in the size of a large packet of smokes, took him over an hour to do the wiring conversion and WOW!

 

Its totally fixed the breakdown issue mentioned above, plus it must be delivering spark better or something cause even my fance said when driving the big leeder "whats happened to the motor it seems much faster?"  Fuel consumption is better too.  In addition a bottle of mercury quikclean is going in the tank every fill which seems to have cleaned the big ol chev up heaps.

 

Thats it, so stoked that for less than a grand a year long problem has been fixed, thanks for all your advice guys tight lines and safe boating.

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 Pilbara WA

z00m's picture

Posts: 1086

Date Joined: 10/05/14

 Good stuff. And good on you

Fri, 2015-06-05 07:38

 Good stuff. And good on you for following up and posting the solution for others when they do the research.

freo fatboy's picture

Posts: 17

Date Joined: 16/10/11

More good news

Thu, 2015-08-20 16:06

 My mechanic also suggested I run quiksilver QUIKCLEAN every tank.

The Leeder has a 180l tank so a third of a bottle of quikclean goes in each time I fill up.

In the last 10 tank fills the old chev has drastically reduced its oil burn to nearly zero, no more smokey black stains on the transom and she revs so free these days.  Mechanic said its due to having proper thermostatt, ss plugs, rings freeing up and reduction in carbon, will take his word for it.

Also put a mercury enertia ss 15p prop on giving 4800rpm at WOT and good hole shot, has upped our top speed to 60km/ph over 50 ish with the old 17p ally and we now use 1 litre per km at 3200rpm = 45kmph.

I do love the sound of that big v8 and having the swim platform out the back.

 

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 Pilbara WA