Reply
 
Thread Tools Search this Thread
 
Old 26 September 2008, 20:47   #1
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,688
Misfire

On my Johnson FastStrike 115GL 2 stroke V4.... stinky old VRO gas guzzler.

Pretty much ever since I have had it there has been a consistent problem with a misfire on 1 cylinder at low revs, always the port side one at the bottom. I've had the plugs out enough times now to be certain it is always the same cylinder, so I'm trying to get my head around why, whether I should be worried and whether there is anything I can do about it.

How does the VRO oil injection system deliver oil to these engines, is it done individually for each cylinder or what is the method of delivery? It runs perfectly under load at anything over about 2000 rpm right up to WOT 5200, but drop to idle and within 20-30 sec there will be a misfire and smoke. When you whack the throttle open it takes a few seconds to clear (only about 1-2 sec if you have been idling for a very short time but sometimes 10-15 sec if you have been idling away for 5 or 10 minutes e.g. alongside a pontoon) and then is fine again. When it is missing at idle there is significant bluish smoke.

The plug on this one cylinder is always wet (and clean, not black/sooty) when I take it out, the others are always perfect, nice healthy light tan colour. It's had 2 new sets of plugs since I have had it, and its always the same one that comes out wet. Plugs are the right type and correctly gapped, just reset them this afternoon and the 32 thou gap had opened to about 40 or so but nothing serious, all the gaps are even.

Does anybody have any ideas? I don't use the affected low speed range much but it can catch you out when you suddenly need power and it doesn't arrive - like when I was out in about a 5-6m lazy swell the other day and occasionally had to get the hell out of the way of something that looked like it had my name on it

What does worry me slightly is that it will almost always be in the "misfiring" state when shut down (idling on trailer before shutdown), and neat unburned petrol hosing down the cylinder walls is probably not a great idea for the long term health of the engine if it is sitting around for a few weeks between uses - but usually not long enough to warrant messing around with fogging oil.

I've done about 125 hours since I got the boat 2 years ago (now a bit over 400 hours on the engine) and as far as I can remember there hasn't been any significant change in the way it has behaved.

Any thoughts would be appreciated
__________________

__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Old 26 September 2008, 21:05   #2
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
How clean? Tan and clean, or like a new plug?


Compression test it.
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 26 September 2008, 23:20   #3
Member
 
Country: UK - England
Town: Essex/Vendee
Boat name: shockwave,Voluntry 2
Make: Pac 22/ searider5.4
Length: 6m +
Engine: 180hp turbo,yam 90
Join Date: Nov 2004
Posts: 1,015
carb

A stab in the dark as there are lots of things to check and i,m sure its what Nos is about to get to the carb may need a clean as the idle jet may have a slight blockage.My post is an early morning one as we catch the ferry soon for hols in france will see how you are getting on when i get back .good luck Peter
__________________
PeterR is offline   Reply With Quote
Old 27 September 2008, 05:04   #4
Member
 
Country: UK - England
Town: Gloucestershire
Boat name: Osprey
Make: Osprey Vipermax
Length: 5m +
Engine: E-tec 300 G2
MMSI: TBC
Join Date: Dec 2006
Posts: 4,013
Lee at Fairweather is a good man to speak to about these older V4's was always a mine of information when I had mine. I think you may find that cylinder always runs at a differnet temp to the rest (can't remember if it is higher or lower) due to the way the water goes round the cooling jacket.

Otherwise you may need to look at the CDI unit to see if that is a problem. I dont think your engine is the one with Optical ignition otherwise I would suggest cleaning the optical sensor on top of the engine or possibly replacing it.

If you do have optical ignition I have the electronic gizmo for setting the timing let me know and I can send it over for you to try out.


Chris
__________________
---------------------------------------------------
Chris Stevens

Born fiddler
Chris is offline   Reply With Quote
Old 27 September 2008, 05:08   #5
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,688
Clean - as in washed shiny clean with petrol, not light tan like a healthy plug should be.

Is it safe to compression test these engines in the normal way? Some engines (the V8 in my Discovery for example) apparently if you pull the plug lead off with the engine running/cranking it can fry the ECU (I know there isn't an ECU in this just wondering if there is anything I should do?)

I think it says it is optical ignition on the plastic cover I took off but I'll check later.
__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Old 27 September 2008, 06:23   #6
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
Make sure you ground the plugs(that should be standard procedure for anything with electronic ignition).


A question-do you have a manual for it? Is that cylinder the one that uses the bottom conrod on the crank?
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 27 September 2008, 07:00   #7
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,688
I do have a manual for it. Not with the boat (or the manual) at the moment, but yes I think from memory the port side cylinders are slightly lower than starboard side (the plug was harder to get at anyway) so that would make that cylinder the lowest of the four - why, is there a known problem?

Just thinking about it I suspect a compression test would show that cylinder to be slightly lower anyway because of the bores being washed with petrol before shutdown and the rings would not be sealing as well? I'll have to scrounge a compression test kit anyway but we should have something suitable at work.

A label on the inside of the plastic cover over the ignition system indicates that part was made in 1997 (engine and boat purchased "new" in 2000 so it might have been old stock).

I changed the HT leads yesterday just to rule them out, but they looked OK to me. I haven't tried it again in the water since that but don't think that is the problem anyway.
__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Old 27 September 2008, 07:07   #8
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
Quote:
Originally Posted by BogMonster View Post
I do have a manual for it. Not with the boat (or the manual) at the moment, but yes I think from memory the port side cylinders are slightly lower than starboard side (the plug was harder to get at anyway) so that would make that cylinder the lowest of the four - why, is there a known problem?

Just thinking about it I suspect a compression test would show that cylinder to be slightly lower anyway because of the bores being washed with petrol before shutdown and the rings would not be sealing as well? I'll have to scrounge a compression test kit anyway but we should have something suitable at work.


If it's the bottom conrod, it may mean your crank end seal is leaking. It's usual for the plugs to look steam cleaned if it leaks.

it may show on a compression test-but the easiest way to tell is to drop the lower unit off,fire a load of premix into the crankcase via the carb mouth and see if it finds its way out via anything other than the exhaust tube. Make sure the plug for that cyl is out and turn it over by hand/slowly to flush anything left out before restarting it-hydraulic lock is bad news.
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 27 September 2008, 16:59   #9
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,688
Quote:
Originally Posted by Nos4r2 View Post
If it's the bottom conrod, it may mean your crank end seal is leaking. It's usual for the plugs to look steam cleaned if it leaks.

it may show on a compression test-but the easiest way to tell is to drop the lower unit off,fire a load of premix into the crankcase via the carb mouth and see if it finds its way out via anything other than the exhaust tube. Make sure the plug for that cyl is out and turn it over by hand/slowly to flush anything left out before restarting it-hydraulic lock is bad news.
Yikes you mean water into the cylinder? sorry don't see exactly what is leaking from where to where? I went out today for an hour or so, and it is exactly the same with the regapped plugs and new leads so no improvement there. Shame as it runs like a peach once you are off and moving with a few revs on.

It sounds like a recipe for a big job to get the bottom off an outboard that apparently was built in 1997 and probably never stripped since (no it hasn't had the impeller changed, ever, and I've been putting that off for the same reason!)

Not having anywhere to work on it under cover is a bit of a bugger too as when the weather is OK to work outside it's usually windy/dusty!
__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Old 27 September 2008, 17:29   #10
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
Quote:
Originally Posted by BogMonster View Post
Yikes you mean water into the cylinder? sorry don't see exactly what is leaking from where to where? I went out today for an hour or so, and it is exactly the same with the regapped plugs and new leads so no improvement there. Shame as it runs like a peach once you are off and moving with a few revs on.

It sounds like a recipe for a big job to get the bottom off an outboard that apparently was built in 1997 and probably never stripped since (no it hasn't had the impeller changed, ever, and I've been putting that off for the same reason!)

Not having anywhere to work on it under cover is a bit of a bugger too as when the weather is OK to work outside it's usually windy/dusty!
Maybe... Does it come out of the water and get flushed every use? If not then it's probably not water in the cylinder as the plug would be rusting.
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 00:50.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.