To re-engine or not to re-engine.......

[James W]

As i'm finally bringing the boat in for the winter in the next couple of weeks, my thoughts have turned to my eternal bugbear, the engine. All I want is it to be reliable, start when needed and to drive the boat forward, whilst not being a potential hazard to me, my family or crew.

The engine in question is an old Volvo petrol engine that many of you have been good enough to help me out with. The petrol aspect does worry me, especially as the fuel tank is situated very close to the gas locker. However, the engine starts fine and generally runs well, but is a 1974 model, has had a few cooling system issues and she does smoke a bit. I do however have an entire engine the same that I can use as spares once the boat is in.

What do the much more experienced members of the forum recommend, taking into account that I bought my boat (a Trident 24) for possibly below what she is worth, leaving me with a bit to spare.

a.) Persevere with the petrol engine, using the spares I now have and give the engine a good overhaul over the next 2 months, saving me money that could perhaps be used for a bigger boat at sometime in the future.

b.) Bite the bullet and buy a new Yanmar (for no other reason that they fit nicely and a lot of Trident's have them), knowing that although I may never get my money back, but at least I will have piece of mind knowing that if I need the engine, it will be there and less likely to be catastrophic should a fire occur.

Thanks loads, your thoughts as always are very welcome!

 

[30boat]

I think you already know the answer.By all means if you're prepared to pay for the Yanmar ditch the petrol engine and get some piece of mind.The thought of a tank full of petrol near the galley gives me the creeps.

 

[theoldsalt]

James,

I get the feeling that you are almost sold on the idea of changing the engine to a Yanmar, and are looking for confirmation that it is worth doing.

I for one think yes. It would be a wise investment if you intend keeping the boat for many more years. however if you think there is a good chance that you may sell the Trident in the near future then persevere with the petrol and save the money towards your next boat.

Whether Yanmar is the best alternative to the petrol if you decide to change is another question but if it a popular choice for the Trident then go for it.

Good luck

 

[Chris.mcc240]

I had a similar dilemma with my centaur except it was an old diesel Penta. After spending x amount trying to keep it serviceable, it was expensive,unreliable, noisy, etc. How ever i did not have the money for a new engine.
How are your diy skills, i sourced a good second hand engine " they are out there" and fitted it myself, really enjoyed doing it. Its not beyond anybody whose prepared to try hard enough.
I now have a boat with a powerful Modern reliable engine and a great deal more knowledge about the subject. All for three weeks hard work and 2k ! Total that includes lifting out..it even looks great after cleaning the bilge building new mounts and repainting etc..

 

[James W]

Cheers guys. I think the main dilemma is that although I just about have the money, like everyone else, i'd rather keep hold of it at the moment if at all possible.

Chrismcc, I like your idea. I'm not a bad mechanic and like a challenge so maybe that's the best way to go, learning as I go and saving labour charges.

I might just have to go for it now though, the time has come for a little bit of worry free sailing!

Thanks again!

 

[aquaholic]

I think the important question is how long you plan on keeping the boat for? Highly unlikely to get your money back on a new engine if you sell any time soon. I am guessing since the tank has been next to the gas since 1974 it hasn't exploded in this time so no need to think it will. If the engine works and is reliable then hang on to your money. I was thinking the same thing with our old boat, then we had a day where we had to motor for 65 miles across the channel to get home and she never missed a beat. Try a long motoring journey and see how she gets on. If all goes well it will give you great confidence in the old girl

 

[Deleted member 36384]

I think the important question is how long you plan on keeping the boat for? Highly unlikely to get your money back on a new engine if you sell any time soon. I am guessing since the tank has been next to the gas since 1974 it hasn't exploded in this time so no need to think it will. If the engine works and is reliable then hang on to your money. ....

I was thinking along much the same lines. Don't spend the money on a new engine as you imply that it is currently reliable and you have a supply of spare parts. Obviously the vapour dangers associated with petrol you are aware of and manage. I would still keep the money set aside for a future replacement if the engine craters big time, always a possibility. If it was me, with what you say so far, and if the engine ran OK and there were no issues with the fuel, I would keep it.

 

[James W]

Mmm, valid points all round as usual guys. More thinking needed....

 

[john_morris_uk]

Fitting the new engine really isn't difficult - but make sure you get it right in all aspects the first time - its much easier to sort out engine bearers and the exhaust and saltwater cooling etc etc when the engine is being installed than when the boat is back in the water etc etc.

Personally I would never dream (this side of a major lottery win) of getting someone else to fit an engine in my boat - but then I am a very keen DIYer. If its any help, I have fitted and removed engines from four boats - and never had a real problem.

PS I have almost always used the boom as a crane to lift the engine in and out with despite the doom and gloom merchants saying you can't do it and it will bend the boom - just support the boom with a spare halyard where you are lifting. Best of luck.

 

[wytco0]

Perhaps I should put this in a new thread but as a novice and having looked at a few boat engines recently it strikes me that changing a boat engine is a fairly simple job.

I haven't worked on a boat engine but having changed several car engines and worked on a few aircraft engines, boat engines look pretty simple.

Are there any issues that make installing a boat engine more complex that it looks? obvious I am thinking about simple sailing boats not complex super yachts etc.

 

[Burnham Bob]

I installed a Yanmar 1GM10 myself. It wasn't difficult although the engine bearers took some work and lining up the engine with the shaft was done by a mate who is an engineer although I suppose i could have done it.

The engine was great - first time start, powerful and reliable. Servicing it myself was easy although there were a few issues that had to be learnt along the way. If you do go for the Yanmar and want to know what i found out PM me.

If the petrol engine is working fine, I'd personally keep the cash until it started getting unreliable. It's a lot of money to lay out and in the meantime if you are not in a hurry you could look out for a dealer reconditioned Yanmar which might be more cost effective - they do come up occasionally.

But if you go ahead, it's a great engine and the self install isn't a daunting task.

 

[Twister_Ken]

Are there any issues that make installing a boat engine more complex that it looks?

Prop shaft alignment.

 

[Searush]

(snip)
Are there any issues that make installing a boat engine more complex that it looks? obvious I am thinking about simple sailing boats not complex super yachts etc.

Twister Ken has only really touched on the issues. I would say the 3 big issues with any boat engine installation are;

Alignment,

ALIGNMENT

& ALIGNMENT

Get that right & the rest is comparitively straight forward. Shaft seals, gearbox, propshaft, bearers, vibration & prop connection are all major issues if the alignment is out. Also. if installing a used engine make sure you use new mounts for it otherwise all the alignment will have beeen a complete waste of time!

 

[wytco0]

Prop shaft alignment.

Yes I can imagine that's pretty critical but is it hard to do? There must be some good techniques to getting the alignment correct, I love watching good engineers doing that sort of thing, its a great way to learn how to do thing properly.

 

[alahol2]

Are there any issues that make installing a boat engine more complex that it looks? obvious I am thinking about simple sailing boats not complex super yachts etc.

As Twister Ken says. You are basically trying to do a 3-dimensional jigsaw puzzle to get the bearers, feet and gearbox output in the correct alignment at the same time ensuring you have access to the filters etc.
Other things that I found frustrating was differences in exhaust diameter from the old engine, differing threads on the old/new fuel piping/filters, different direction of prop rotation.
None of this is particularly difficult but does require a lot of forethought and planning. Vitually no two marine installations are the same by the time you come to replacing an engine.

 

[Tranona]

Have been through this twice in the same boat that I have owned for over 30 years - and worth not a lot more than your Trident. The main consideration is how long you want to keep the boat and what are the alternatives. If a replacement costs the same as the combined sum of the current value and the new engine, then sell the boat and buy the better boat. If you are happy that a replacement will be more than that, bite the bullet and fit the new engine so you benefit from it the rest of the time you have the boat.

I replaced a Stuart Turner with a Yanmar 1GM in 1992. Similar performance, but it worked, although still a bit marginal on power. No room for the next size up. Replaced in 2010 by a Nanni 14, not because there was anything wrong with the Yanmar, but decision to keep the boat even longer, and the Yanmar had a market. Sold it for just about what I paid in 1992 and it is performing well in its new home. Hope the Nanni will do as well over the next few years.

If you are going to change the ideal would be to find a secondhand Yanmar like mine, but they are rare. Could have sold mine 3 times at least from one advert. If buying new then a Nanni or Beta 10 would be a much better bet. Same size as the Yanmar (as is my 14, but you don't need the extra power), smoother quieter and fresh water cooled. However, be prepared for an additional spend at least £1k on the base engine as you will need to replace the stern gear, controls, exhaust and a new fuel tank. Not worth skimping on these bits, not only will the old bits not be matched to the engine, but will be worn out.

Not a difficult job if you take all the old stuff out. The Yanmar (if you go that route) can just about be handled by two people, but the Nanni is a bit heavy - I used a fork truck to lift it in. Building the engine beds up will be the biggest job, but you may find you can have steel feet made up to fit your existing beds.

Hope this helps.

 

[pappaecho]

Replaced a Perkins 4108 with a Beta 35 HP 3 years ago, and had it "professionally" installed and it was a disaster. I should have repaired the Perkins at a fraction of the cost and hassle.

In your case however, the fact that it is petrol, with both safety and reliability problems, would tip me in favour of a diesel. It wont come heap,but at least it will be safe and reliable

 

[Evadne]

Have been through this twice in the same boat that I have owned for over 30 years - and worth not a lot more than your Trident. The main consideration is how long you want to keep the boat and what are the alternatives. If a replacement costs the same as the combined sum of the current value and the new engine, then sell the boat and buy the better boat. If you are happy that a replacement will be more than that, bite the bullet and fit the new engine so you benefit from it the rest of the time you have the boat.

+1. If it works and you are keeping the boat for the long term, then keep the engine until you have a reason to change. The only thing that would worry me with petrol is that, with a diesel I've had fuel leak into the bilges on occasion. Smelly, but not explosive. If you've lived with it and it doesn't leak, then it's unlikely to be a problem. IMO petrol isn't a problem, as long as it stays in the tank until needed.

Selling, petrol is always going to put people off and would be a reason to change to a diesel or drop the price to compensate.

 

[Ruffles]

Apologies for being negative but I suspect it's a lot cheaper to buy a boat with a newer engine than to buy a cheaper boat with the original engine and replace it.

Bit of a 'if you want to go there I wouldn't start from here..." response but there you are.

 

[ianj99]

Twister Ken has only really touched on the issues. I would say the 3 big issues with any boat engine installation are;

Alignment,

ALIGNMENT

& ALIGNMENT

Get that right & the rest is comparitively straight forward. Shaft seals, gearbox, propshaft, bearers, vibration & prop connection are all major issues if the alignment is out. Also. if installing a used engine make sure you use new mounts for it otherwise all the alignment will have beeen a complete waste of time!

The biggest issue re alignment when changing an engine is likely to be the difference in mountings & bearers. eg:
Are the existing engine bearers useable? They are too high then you have a bigger problem than if too low.
Are they long enough?
Have you access to drill new holes for the engine mounts?

If preliminary measurements make the engine swap reasonably straightforward then actual shaft alignment is not too difficult (I note no posters have actually told you how to do it!)

If there are going to be major problems with the installation, I'd not bother. Will the fuel cost savings be worth the expense?
Is replacing a relatively light & quiet petrol engine for a heavy, noisy diesel going to spoil the refinement?