I'm looking into buying a boat that has an old volvo md7b saildrive, the owner states its been serviced yearly. The problem is its very rusty on the outsides - what would you do
If you are concerned then think about having an engine survey.
Make sure it starts trouble free from cold, and feel the engine to make sure it is cold first.
Find out what was done as part of the servicing. Was it winterised every year.
If the engine starts without trouble, has been thoroughly serviced each year, and gets a clean bill of health from an engineer then there may be no problem and the rust is cosmetic. You can degrease it, clean off the flakey bits with a wire brush and touch it up with some engine paint.
I'd agree, rust on the outside of the block is not a problem, unless it is extreme and indicates inundation. If it has a new oil filter and anode, and the oil is a reasonable colour then it's been serviced recently. If it starts from cold and runs without smoking then I'd accept it at face value. If he has bills for servicing and/or parts then that's a bonus. Most owners "service" their own engine 'cos it involves an hours work for an idiot like me, plus parts (filters, oil, plus anode and impeller where necessary). Anything more than that I call "repair", rather than "servicing". If you're unsure then an optical boloking by an engineer is worth the money.
A rusty engine eh, well either the current owner has nothing to care about or hide ! as it not been given a lick of paint to help sell it.
The condition of the rest of the craft might give more clues to the care the owner applies. My engine is bright/shiny and new looking, and 25 years old, but I can see for any signs of trouble and work on her quite simply, that me though. It runs well as only a few tanks a year is ever used so v. little use.
As long as no rust on shafts to upset the seals then it might be fine, take a look at any seal/gasteks, to see signs of leaking.
As above if she starts from cold, no smoke when warm, sounds fine, and keeps cool, etc, then it depends on the overall condition of the boat v the price.
If you have little mech experience pls do take an engineer to offer advise, his fee will put your mind at rest, or not : )
It was a frivolous suggestion, a fact lost on you by the sounds of things…
Think about it though, an MD7B circa early 80’s, that’s a good 25+ years, an engine which is raw water cooled. It may very well be rusty on the outside, its most certainly going to be tired on the inside too.
The MD7B was 17hp, so keeping the theme Volvo Penta, a D1-20/130S engine package retails somewhere around the £5K ex the VAT.
By the time you thrash out a deal you would expect to be paying less than £4K, a decent fitter is going want a good £1K for their time, sundries, boat ashore costs, etc etc…
So, no not a trawler engine, that is a daft suggestion…
No where did I suggest the seller provide a new engine, it was merely a suggestion to consider the costs involved further down the line with an older boat, and as such perhaps use this as means to negotiate a more favourable asking price for the yacht.