Volvo Penta 2002 slowing down and stalling

**technodom** · 10-04-12, 23:40

Hello all,

I am looking for some help and advice please.

I recently bought a 1979 Seamaster 925 - 30ft yacht, with a Volvo Penta 2002 engine. I had a full survey done but could only get the engine checked ashore by a marine mechanic who wrote a short report saying the engine was fine.

I had a full engine service done straight after buying her - change of oil, filters etc, along with a new cutlass bearing and stern gland replaced for peace of mind.

On my first journey out with her she started fine - using the cold start method, and she ran fine for an hour then on my return to the yard she had a short slowdown in revs where she felt like she was going to stall but didn't, then revs came back up and all was okay again.

The next trip out, she went for 20 mins then slowed down and sped up and repeated this every 5-15 mins, no regularity and when the engine was running at a normal pace. Near to the end of this 1 hour trip she stalled after slowing. I turned the key off and back on a gain and she started perfectly and off she went again.

I then took her on the journey home from Hamble to Chichester and she didn't slow or stall all day, mind you we had lovely weather and sailed most of the day so not necessarily a change.

Today I took her out for a couple of hours and she stalled 4 times, was running up and down the rev's almost the whole time, she felt like she was being strangled and I felt very nervous she was about to pack up. She did start straight back up after each time she stalled.

The only other info I noted was a small cloud of white smoke when I start her up first thing and now a small trail of white smoke all the time. I made a sound recording of her today and will try and upload the file if it helps anyone.

Hope someone can help, the mechanics are saying it's going to be 2-3 weeks before they can take a look due to the time of year.

Sound file link https://jamesesq.wetransfer.com/dl/D...376f980302e579

Thank you

Dominic

**peterN** · 11-04-12, 11:30

Could be a number of things. I have had similar problems with a 2003T. If its not overheating, and this should show up on the instrument panel, it could be dirty fuel or air getting into the fuel system. I have had dirt from the bottom of the tank causing the engine to hunt. It would only run smoothly at low revs. You may have bacteria in the fuel if you and the previous owner haven't used a biocide regularly each time the boat is refueled. Air in the fuel can easily come from improperly seated fuel filters or bleed points such as bangos and injector connections. These are just a few suggestions from my experience, but I'm no expert. Hope they help.

**MoodySabre** · 11-04-12, 11:43

I've never used a biocide so this might only be an issue with white diesel.

This sounds like fuel starvation - I'd start by clearing the fuel tank breather. I suppose it might be **** in the bottom of the tank blocking the take off - worth checking if you have an inspection hatch.

**Stemar** · 11-04-12, 13:39

If the filter's clean and there's nothing else obviously amiss, it's worth remembering that quite a number of tanks have an undocumented strainer in the fuel outlet. This can obviously cause problems if it blocks and if you don't know about it, it can be quite hard to diagnose.

**DJE** · 13-04-12, 08:57

Originally Posted by Stemar

If the filter's clean and there's nothing else obviously amiss, it's worth remembering that quite a number of tanks have an undocumented strainer in the fuel outlet. This can obviously cause problems if it blocks and if you don't know about it, it can be quite hard to diagnose.

That's what stopped mine in a flat calm in the middle of a busy shipping lane! Somebody had fixed a bit of gauze to the end of the fuel take off pipe inside the tank.

**technodom** · 13-04-12, 16:17

Engineer has been and gone!

He found 3 things, firstly he isolated the problem to the fuel system by using a jury rig to bypass the fuel system and go straight to the engine. He then found the fuel tap to cut off the fuel was made of copper and corroded, replacing this improved the fuel flow but not completely, he was not able to properly bleed the system after replacing as the primary filter could not be bleed properly due to the long bolt replacing the screw. He replaced the whole filter. He then found the return pipe which was also made of copper and slightly bent, he replaced this with high pressure hose. They have told me to go out and have a blast this weekend! I'm heading out tonight and will let you guys know how it goes. Fingers crossed.

**Vamoose** · 11-04-12, 13:47

I had the same problem with a VP2002 .

I suggest you change both fuel filters again. You may have stirred up muck in your fuel tank which has clogged them up.

If it cures the problem for a short time then it gets worse again you will know thats the problem.

If it does not cure the problem you have only wasted about £12

**kacecar** · 11-04-12, 14:32

I once had what would seem to be a similar problem with a VP2003. While running under load the motor would suddenly slow and threaten to stop. Unlike the slowing one gets with blocked filters (I've had that problem too) it could be revived with a quick burst of throttle. There didn't appear to be an issue while it was idling. The problem got worse over about 30 hours motoring (it was a long windless trip along the southern coast of England and then across the Irish Sea to Cork) such that by the time we arrived at our destination I was having to "catch" the revs every few minutes.

After much faffing about with filters, injector bleeding and the like it turned out to be the fuel pump itself. It was the old style unit with the replaceable diaphragm and replacing that didn't work but I noticed the one-way valve on the fuel feed (in the pump top) was loose - I didn't realise it at first but it's meant to be a tight press fit. What was happening was that the pump would suck fuel in on one stroke and, on the next stroke with this valve loose, would pump some of it back out the way it had come in! The immediate fix was to peen over the edge such that it stayed in place - a bodge that has lasted years. Eventually I changed the fuel pump for the newer sealed type (reportedly much more reliable than the old serviceable type) but the old one remains a useable spare.

I'm not saying this is definitely your problem - other posters have already suggested lots of alternatives and it might, for example, also be a split diagphragm - but it might be worth a check.

**West Coast** · 11-04-12, 16:19

Similar problem with a 2003 a few years ago, turned out to be an air problem caused by a loose banjo fitting to the fuel pump.

Interesting that so many solutions to recent posted problems for 2000 series engines have focused on the fuel pump! Seems this could be a common problem? Anyone know how much a fuel pump is? Is it worth having a spare on board?