volvo engine trouble

[paulwilliams]

Ive got a volvo aq145. Its been running fine for the first part of the year. Anyway started the engine this weekend and sounded like it normally does anyway after about 30 seconds started running it turned really rough and sounded like it was missing, vibrating alot etc. Revs where also running lower than id have expected and was idiling very slow and very rough. At higher revs things smoothed out. Starting it from cold it did the same again ran perfectly for 20 or so seconds then went all rough again and revs dieing away. The engine was serviced a couple of months ago and was running sweet including last weekend! Very annoying! Can anyone help? Thanks Paul.

 

[brianrunyard]

It sounds like a fuel problem to me, possible a blocked slow running jet.
When you start there will be excess fuel from the accelerator pump, so it will be ok for a few seconds. At higher revs the main jets take over.

 

[Davy_S]

I would suggest checking the fuel filters first, then take off the air cleaner, rev the engine up, quickly put your hand over the intakes of each carburretor in turn, if there is a blocked jet, it may clear it. Otherwise have a look at the plugs and points, mine had a condenser problem once, but the engines are really very simple to work on, at the end of the day they are just a Volvo car engine.

 

[Peanuts]

As already mentioned it is only a car engine. I would be looking at the ignition side of things first - dist.cap, rotor arm, points and condenser and checking leads, not forgetting the spark plugs, just because it was serviced recently doesn't mean there isn't a problem with a plug for example. Once that lot has been checked 'satis' I would then move onto the fuel pump and check the strainer and last of all consider the carburetor (why do people always what to take these apart?) and check the idler jet, only blow through no poking with scribers or other metal pointy things. At this point I would mention that I assume you have checked the exhaust manifold and its not putting water into number 4 pot. How old is the manifold?
Anyway best of luck and let us all know the outcome of your problem.
Steve

 

[brianrunyard]

[ QUOTE ]
(why do people always what to take these apart?) Steve

[/ QUOTE ]

Because the symptoms point to a blocked slow running jet.
1. The engine was running fine last week.
2. Now it wont idle.
3. The engine runs fine for approx 30 seconds.
4. The engine revs ok.
5. If he stops it and restarts it's ok for about 30 seconds again.
In my experience dist caps and condensers tend to show up under load not at idle, if it was the ignition coil number 5 wouldn't apply.
I therefore suspect some dirt has been dislodged when it was serviced recently, possibly when the fuel filter was changed, and it's found it's way into the slow running jet.

These are my reasons, happy to hear yours as I'm always willing to learn.
Regards,
Brian
Poole

 

[paulwilliams]

Thanks for the replies. The filter was changed and the guy who did it said there was a fair about of muck in it so it coud be possible something has found its way through.... thanks for that.
Everything from the coil to the plugs was brand new 5 weeks ago so im sure everything is ok there unless something has got dislodged somewhere but i cant see how....
If it is muck in the carbs what do you think of the chances of carb cleaner, hand over the air intake etc working or is a strip down looking more likely?
Is there an easy way to identify which carb is playing up?
Thanks Again, Paul

 

[Peanuts]

The plot thickens, it might of helped if you had mentioned in your first post about the muck in the filter, although I still stand by my first reply (although I do agree with the other replies). So maybe the way forward is to check the idle jet, above the throttle shaft adjuster screw there is an adjuster screw (small one), next to that is the idle jet, you can remove it to give it a clean without dismantling the carb. Whilst you are there in the bottom of the carb body is a larger hex head, unscrew that, inside is a filter, it might pay to inspect, clean and refit.
Once again let us all know how you get on, we all learn from these problems

 

[Davy_S]

OK Lets accept the fact that everyone on here only wants to help! also the engine is a twin carb, not single carb. you have been given good advice on how to check the nozzles without stripping the carbs or altering the sync of both carbs, try what you have been advised, and then report back, these sort of problems are common, and solutions are helpfull to future problems forum members may encounter. It all helps!