sealine 290 - AD31 diesel problem

[mickyb]

Hi there.

I'm completely new to this and this is my first post.

I recently went to view a beautifully kept Sealine 290 with twin Volvo AD31 130hp diesels and i'm really hoping to buy her (my first proper sea going boat).

After thoroughly looking round the boat the owner took us out for a spin.

There were four adults on board and as the owner opened the throttles she refused to get over the 'hump' and onto the plane, we were sat at 10 - 12 kts with the bow in the air and no matter what he did with the trim tabs, she just wouldn't get going... There was more black smoke than I would have thought was normal coming out of the back and with both throttles wide open the engines weren't revving much past 2000 - 2500 rpm - certainly no where near 3800 (which volvo say they should get to).

Now i've done as much research as I can on the net and spoke to various people to try and find out what the problem is (im a bit 'green' when it comes to problems like this with diesels).

One of the obvious things that was apparent was the hull and outdrive legs were by no means clean (v green and slimy). So fine, this could be why she didn't get up on the plane, but to the novice, it doesn't explain why the engine revs remained so low? - I thought the engines would do their business regardless of the hull being mucky.. (just move a lot of water but still spin up).

The other thought I had was this... The owners of the boat (v nice couple incidently) generally cruise around at 8-9 kts and rarely open her up. We once had an inland/estuary boat (Freeman 28) with a diddy Volvo 2003T engine and this had a similar problem after we just bought her. Obviously the boat was never capable of getting anywhere near the plane, but when we opened her up, there was hardly any grunt. It turns out that because of several years of canal speed cruising, the turbo was sooted up to the eyeballs and wouldn't spin. We stripped the turbo down and the problem was solved.. Could the sealine have the same problem? - I think that may explain the black smoke (and it was coming from both engines - the transom was black on both sides when we got back to her berth).

When we came back into the marina, I asked the owner to open the engine bay and start the engines again and rev them in neutral - see if we could hear the turbos.. The there was no sign of a whine, but I subsequently read somewhere else that on AD31s you can't hear the turbos whine when in neutral, the engines have to be under load.

What I hope (after all my reading and asking questions) the problem is, is that because of the dirty hull, the boat couldn't get on the plane, therefore due to water resistance on the props the engines could not reach sufficient rpm for the boost to come in, and so the power was held back creating a vicious cycle therefore meaning lack of performance and fast displacement speed only. Im starting to think the black smoke may be caused by too much fuel going into the engines, and with a lack of revs - a lot of this would be unburned.. ? Does anyone know could this be plausible?

Please forgive me for such a long post, but this is a lot of money for me to be spending, and I just don't want to be landed with huge bills when I get her home (bit like what happened with my last girlfriend )

Many thanks
M

 

[RobWales]

The ad31's are not the best VP engines by a long way! I know I have them in 150hp guise in my Corniche.....

My advice..........

Shop around and gently walk or perhaps run away from this one,there could be a number of things wrong or it could be simple as in a dirty bottom, but if the owner is serious about a sale he would ge it performing properly before he takes a prospective buyer for a trial!

Good luck.
Rob

 

[neale]

Almost certainly due to a dirty bottom. Other likely causes, faulty turbos or wrong size props.

I think a serious problem is unlikely, although cannot be ruled out altogether.

If the boat is good in every other way, ask the seller to get it lifted, pressure washed, check size of props and put back in (at his expense). Take it for another run. If it still won't rev up properly and the props are the right size, walk away.

The owner will have to get it sorted otherwise it won't be sellable.

 

[Chris_d]

I've got AD31's in my similar sized boat but they are the 150hp versions, I would think the 130's will struggle unless perfect conditions anyway, my 150's do if there is a bit of a swell for instance. The performance you describe sounds like dirty bottom and partialy blocked filters, maybe dinged props as well, certainly mine will not get over the hump and sits at 2500rpm approx if everything is not perfect. However you always hear the Turbos whistling up at this speed even if the boat fails to plane, black smoke doesn't sound good and indicates over fueling so sounds like seized turbos.

My advice would be to have the owner lift the boat, have it cleaned, props checked , filters changed and prove it does perform. Or better still look for a 290 with AD41's which will be a much better performing boat.

 

[Pendana]

I used to have AD31's 130hp in a Sunfury which revved immediately to 2400 RPM and then would take about 15 seconds to wind up, get over the hump then rev right up to 4000 rpm. I thought they were great engines and dead easy to service. Cruise all day at 3300 rpm and 20 knots.
As Neale says it could be dirty bottom or knacked props but from your description it could also be that the turbo's may need an overhaul. 2500 RPM is when the turbo's start to produce boost (or should do) and it may be that that is the reason they never went beyond that figure. The turbine side of the turbo’s do wear away over time. The owners call though if he is keen to sell.

 

[volvopaul]

sounds like the bottom, though did you have an out of water survey? have one when buying a sealine to look for stress cracks etc.

When the boats out have it washed off then try another sea trial, make sure the legs are trimmed right in to push the bow down and dont take so many people with you or ask them to sit inside in the bow area. trim the tabs down too.

Maybe the turbos are stuck you may also find if its been pottering around the rivers for years the intercoolers are blocked causing air starvation, also these engines do suffer from no performance if the air cleaners are dirty, ive also had one with the intercooler rotted away loosing all boost pressure,

I would advise an engine and drive survey, pm me if you would like me to help with that, it may save you a fortune in the long run.

 

[AdeOlly]

I have twin AD31s in my boat, but the 150hps. I agree with all that's been posted here. With my boat barnacle and weed encrusted props alone are enough to prevent the boat getting onto the plane. So, if they looked like this...
View attachment 1160
then the boat would perform as you describe, though the black smoke is indicative of another problem, lack of air or overfuelling, as already said.

Weak points I know about on these lumps, at least the 150s, are head gaskets and water circulation pumps.

Happy hunting.

 

[Viscount]

AD31s

I've a 285 with twin AD31 130hp. Dirty bottom and gear is the most likely (and simple) problem. If the boat won't plane, the revs will be limited to the level you indicate. It is correct that you don't hear the turbos unless under load. Black smoke (not too much though) seems to happen if the engines are under overly heavy load which I suspect they are if full throttle is applied and she won't plane. I had exactly the same symtoms last year and it was purely fouling.

A test that can help is to try each engine under load on it's own with the other in neutral. If the performance is the same (likely to be 8kts only), the chances are it is the fouling unless some other problem is causing performance problems on both sides (which could be props).

Goo luck!

 

[Morpheous]

Having relatively recently purchased an oldish boat...

If you are not mechanically minded like me an engine survey is highly recommended. But even before that you can work out what the expected performance should be and only make an offer if the owner has already agreed to have the issue sorted. Hopefully as everyone else points out it could be a simple fix. But bear in mind once you have engaged in the purchase process you may find you are paying for lifts and surveys to confirm it's all done. I was shocked at how much I spent just going through the purchase process, not counting the actual cost of the boat.

I knew the boat I ws purchasing was due for a service, the mechanical survey picked up quite a few non service issues that I then negotiated on.

 

[spannerman]

I'd take out the airfilters and check with your fingers if the turbo will spin, if not this is the reason for lots of smoke and no go. I'd then severely beat him down on price as its not a big job to clean the exhaust outlet on the turbo which is where the crud will be.
I did this on my first Saab turbo I bought, the trader didn't know anything about turbos and I knew it was just an £18 rep kit for the waste gate, so he backed down on price when I told him the turbo wasn't working properly and it could be big bucks to get running right and therefore saleable.

 

[mickyb]

Sealine with AD31s

Many thanks to all of you for your advice, it really is appreciated.

The owner instructed the Volvo service man to have a look at the boat and engines and he has taken her for a sea trial. He encountered the same problems as we did and the boat wouldn't plane. I called him yesterday and he really seemed to think the problem was growth on the bottom and said "when you put both them hammers down, it should leap out of the water" he seemed to think the engines were in good condition and said it was a nice installation (incidently engines have done 500 and something hours) but obviously he wouldn't confirm there was no mechanical problem (covering his a55 I presume). Her did say the first thing he looked at were the turbos (as they are easy to check) and he couldn't see a problem with them.

The volvo guy did however discover that the outdrive rams need changing on one side as the leg wouldn't tilt and the boat would need to come out of the water for this work to be done. The owner does understand that these problems all need sorting out before he can sell. So, the plan is to have her lifted, the engineer will replace the rams and the hull and stern gear will be cleaned. Once back in the water I have been invited back for another sea trial to prove she will perform.

I presume that if/when she gets on the plane during the second sea trial and the black smoke stops, I can safely assume she is good to go, so can make an offer . Also, with the Volvo engineer checking her over - Can I not kind of call that a little engine survey??

I really do hope it all works out, I've seen plenty of boats in my time, but this one for her age is like new! really nice condition..

Do you think how im going about this is all okay?

Again, many thanks for all your help, it really is nice that so many people are happy to give their advice to a newbie sea dog..

Cheers
M

 

[seamaster30]

Do you think how im going about this is all okay?

Are you going to have a proper boat survey done as well? - You should really, and most insurance companies will want to see one before they will insure you anyway.

My big tip, unless you are fully aware of any work required and the costs involved, is to get any problems in the survey sorted at the vendors expense before you complete the transaction rather than accept the discount to get it done yourself.

I got a discount to cover the cost of new cutlass bearings, only to find the shafts were worn as well, and my £60 bill escalated to £2000.

Good luck and I hope it all goes well for you.

 

[paultallett]

Hi Mickyb,

Glad to hear you've been bitten by the bug and I hope this all turns out well for you. I couldn't agree more with Seamaster.....A good survey will easliy pay for itself.

I remember being in your position and not being able to wait to get out there. If I can give one small bit of advice, it's be very paitent. Whilst all of these problems are being worked out by the owner to get a sale, it's saving you money in problems you'll encounter later down the road. If you get the survey done whilst she's out of the water, this will save you the cost of another lift whilst being surveyed.

Don't rush in to anything, think the problems through and make sure your happy before going ahead, you will have things go wrong with the boat that you didn't even know about, making the stuff being sorted now even more important. Get it wrong at the start and it could cost you big time!!! But take your time and you'll reap the rewards.

Good luck,

Paul.

 

[davedpc]

Bet its dirty bottom and outdrives plus filthy air filters. Let us know how it pans out.

 

[mickyb]

latest up date

Hello again all..

I went back for another sea trial on the boat. She was out of the water when I arrived with a lift booked for 1/2 an hours time. The bottom had been cleaned, she was freshly antifouled and the stern gear was mint. It turned out she needed two new rams on one of the outdrives, which the owner had instructed volvo man to do, whilst he was there he also changed the outdrive oil and the anodes.

She was lifted back in and we set off about 15nm back to her berth. Once we got out of the speed limit, the wind was blowing a 4-5 and the sea was fairly lumpy, we opened her up and she did it!! she gurded her loins and got up on the plane.. It wasn't warp speed but we were doing about 17-19 kts with 4 heavy blokes on the back (okay not much fuel though) but in far from ideal conditions. Once we got round a headland, the sea was a bit calmer and we had another go. This time, i did the following.. tabs all the way down, legs fully trimmed in and this time she got up to 23kts, I reckon you would get 25 out of her in smooth seas (which is what the owner said he could generally get).

My observations were as follows...

1 As the day went on the max engine revs increased and therefore the power - almost as if they were loosening up, indicating to me a lack of use at higher revs in the past.

2 Revs on both engines got upto 3100 - 3200 rpm at full throttle (as I say giving just over 20 kts. I did think these engines should rev to nearer 3800 if Im honest (and I cant imagine they are the wrong props (duo props) Do you young men/ladies think thats normal?

3 there was a small amount of black smoke coming from the port engine at max rpm (it turns out the injectors on the starboard side have been replaced a couple of years ago so that could be it)

4. I tried idling one engine whilst going full power on the other and vice versa, both engines gave the same revs and about 8kts as should be normal.

Conclusion..

She did perform albeit she was pretty much under full power, the conditions were far from ideal, she is a beautifully kept boat, the bit of black smoke is probably either a dirty filter or it needs new injectors - it may cost me to fix, but I don't think it means buying a new engine..

Decision..

I had to buy her and she is coming up north to fleetwood in a couple of weeks!

I got her at a good price and figured even if I have to spend a little bit - fair bit - quite a bit on the engines I would still want to own her.

Please don't shout at me you lot!

Thanks for all your help
M

 

[CMJ]

Great post and thanks for the update. No shouting from me - you only live once!
Good luck and I'm sure she'll be great.

 

[AdeOlly]

Congratulations on your purchase.

The performance sounds about right, though as you've said they are still down on revs. Ref the port engine, the injectors are quite possibly the problem, but is the air filter clean? New set of tips for the injectors is about £45 ea fitted (just done mine), and I think service exchange injectors are about £70 ea. Replacement is a two hour DIY job if you're feeling a bit brave, but you should use Volvo's injector extractor tool to avoid disturbing the copper sleeves they live in.

Enjoy

 

[Elza_Skip]

I hope you really enjoy her!

It is really really informative to hear the process you went through so thanks for letting us know the outcome

 

[Pendana]

Thanks for keeping us updated. The engines should reach 3800rpm. The fault may be just one engine which brings the other down. Try opening up one engine at a time they both should achieve the same rpm probably between 2300 and 2600. If one is lower than the other, thats where to start looking. If you do have the injectors overhauled, just take them to the local Bosch injector people, they have the kit to clean test and re-shim etc at about £30 each.

Good Luck.

Eddie

 

[Frontier]

I have 31's on a similar size boat. I need to have all the weight forward. We always put all our loose junk on the front berth.

I had a lot of trouble in 2008, eventually needed injectors, refurbished turbos and fuel pumps refurbished. Boats of this size do need to be clean or they take an age to plane.

Air filters have a big impact so replace them regularly. You will get a bit of smoke on the days when its struggling to get up as the fuel is going in but the revs are not high enough to burn it all up.

I had Col of this forum work his magic and as well as fixing the problem she went from just under 2 MPG to 3.5MPG, quite a dramatic increase. (and no smoke)

Fully loaded with fuel water and 4 adults she still struggles to get up, have to get the Mrs to go and lay on the front bunk with all other heavy things we have onboard (not suggesting the Mrs is heavy of course! )

Once she planes she should keep herself clean. With two adults and a chhild and the fuel down to 3/4's we seem to get up quite easy. By the way keep the legs in when moored so things dont grow on the rams, if they do they can cut the seals as you trim in and out.

Good luck, I hope you have a great time.

D