Volvo V8 Petrol Continued

[Fire99]

Hi All,

Well the saga of the AQ200d V8 Petrol engine continues.
I drained the tank down at the weekend and replaced the fuel.
After much adoo the engine ran fine on the pontoon and under light load. Took her for a run and faltered when the revs rose and the engine just wanted to fade away..

Anyway, today after double checking water trap filter / mesh carb filter etc.. engine ran perfectly in the Marina... tested under light load and without for a reasonable time..
Took her for a run and all the way out the creek at low load she ran fine.. pushed the throttle down and she was hesitant finally not getting further than 2.5k - 3k revs.. then faded away and died... then refused to restart at all.. would fire then immediately fail.

Anway after a very vaulable tow back to Tollesbury.. left for an hour or 2 and then restarted fine even under light load!!! annoying? very!

Anyway after a chat down the marina the current guess is Electrical since the fuel all seems ok. Possibly a breaking down coil?? what do you guys think?

Anyway.. a couple of questions.. where can i get a replacement coil for reasonable money.. (Its the one with the resister bolted on the side)?
And while im at it, do you know where i can get a bolt on electronic ignition module for the engine? (ive heard a few people talking about them)

Anyway a bit downhearted on this one at the mo (after all the great weather this weekend) so any help as ever is appreciated... (before i give up and defect to sailing..)

thanks,

Nik

 

[misterg]

Making a number of assumptions.....

The manual for the Rochester 2 jet carb is here and the fault-finding flow-chart suggests the 'power piston' might be sticking.

<edit> If I understand correctly, this device should open up and provide additional fuel at higher loads / revs.

May be very wide of the mark, but sounds like fuel starvation, rather than electrical.

Andy

 

[Fire99]

Thanks for that..
Another twist to the tale... However, when the problem occurs she gets rougher and rougher then refuses to even idle and ultimately refuses to even start which if it was that part i would assume the engine would then run ok if you went back to low load/ idle..

 

[ArthurWood]

Check that thing I told you about earlier - if it has one. I had very similar symptoms on one of my Mercs in the Bahamas and we thought at first it was a bent prop or shaft, but it wasn't. It was the ignition module with corrosion on the connectors. Engine would rev in neutral, but under laod was very rough and would not get past 3000 rpm. Eventually it died. I've had the problem since and knew how to fix it. I wondered how water could get into the ignition system and eventually noticed that one of the pull-up knobs for lifting the cockpit floor panels was immediately above it.

 

[Sneds]

I got the bits you mention from Coastal rides, for my Volvo V6 (no I don't work for them)
www.volvo-penta.biz
Good luck

 

[Fire99]

Thanks for the replies.
Sadly my VP-V8 doesn't have anything as 'new fangled' as an ignition module. Mine has Points burried inside the distributor.. This engine dates back to when i was in Infant school..!!
However i think a change of coil may be worth a poke..
Speaking of Points does anyone know anywhere in the UK where i can get an Electronic Ignition module? I've seen the place in the USA which does them but i'd rather source one from over here as it should be a bit quicker and easier..

thanks,

Nik

 

[dpb]

I think it might be worth checking the cylinder compressions, first when cold, then again when the no start condition has developed. A problem here could lead to the symptoms you describe. If all OK you can then concentrate on the electric and fuel systems knowing the pistons and valves are doing their job OK.

 

[Ramage]

Absolutely classic symptoms of a faulty coil. Engine dies then will not restart for an hour or so. Coil cools down and restarts.

Get a new coil and a spare! /forums/images/graemlins/smirk.gif

 

[Fire99]

Thanks,

That may be a good thing to check.. However the only flaw in the plan is that in the marina she runs up ok and i cant put enough load on her there without trying to pull the pontoons off their mountings and i dont want to do another run out only to 'konk-out' up the river somewhere..

I'll see what i can do..

 

[misterg]

[ QUOTE ]
..... she gets rougher and rougher then refuses to even idle and ultimately refuses to even start which if it was that part i would assume the engine would then run ok if you went back to low load/ idle..

[/ QUOTE ]

I agree with your logic above - sorry, I thought the problem was the power 'fading away' at higher revs. (I thought the failure to start may then have been due to vapour locks after the engine got too hot from running lean at higher revs, but this doesn't tally with the symptoms).

Andy

 

[dpb]

I know what you mean having had similar problems myself in the past.
You have to way up the time it takes for trials compared to taking the boat to a mechanic that has the facility to run the engine under load on a dyno facility and can do all the checks in one session. I have resorted to this in the past when I had similar symptoms and had lost several weekends trying to sort it. Dropped at mechs on monday, all sorted by Friday. The bill was not that bad as they did not take long to find the cause. And that time it was the coil.
I appreciate this might not be so easy if you have a larger boat without a trailer, but worth talking to them anyway, especially if your priority is getting out on the water!!
Let us know how you gety on.

 

[Fire99]

Thanks..
Good logic..
I've decided that i'll try a few basic steps which i can do fairly easily (coil, checking points etc) and then if still no improvement i'll resort to mr Mechanic time as i agree you could spend valuable good weather days doing trial and error stuff..

Does anyone know of a good, not rediculously expensive, marine engine engineer not too far from Tollesbury in Essex? Preferably someone with 'Old School' engine knowledge regarding Carb fed V8 petrol engines.

 

[sonarbell]

Have a look here. They do coils aswell

http://www.lumenition.com/newtronic/system/index.html

 

[AdeOlly]

I fitted electronic ignition to the AQ211 V8 on my very first boat about three years ago. Made sod all difference to the way it ran, which was badly. A coil is def the best thing to fit if it's old as they do deteriorate over time, and it's when they heat up they misbehave.

Another thought - is the timing advance working okay and not sticking in an advance position when hot?

 

[sonarbell]

Dont forget that most type Electronic ignitions just do away with the points, they dont get rid of the coil aswell, so fitting leccy ignition wont remove the coil issue if thats where your problem lies.

 

[Fire99]

Hi there,
Yeah i did know only the points would be replaced by electronic ignition..It was just one old fashioned device i quite liked the idea of junking. I remember when i first started driving hearing the starting benefits etc of electronic ignition and is just another thing to not worry about.

Regarding the coil, i spoke to a very helpful chap at Coastal Rides (even though they seem inundated with people who have broken their engines over the easter weekend) and have ordered a coil and fuel pump from an AQ200d they had on the shelf.

Before getting too involved i'll try the coil first then the pump and then reassess.. Hopefully the parts will arrive by this weekend so i can have a try....