7 Essential Steps When Assessing A Marine Diesel

It doesn't matter if you're looking at a small 300HP diesel engine, or a pair of 1500HP high performance engines - follow these 7 steps and you'll have the best chance of finding a good engine. Whether it's a Yanmar, Volvo, MAN, MTU, Caterpillar, Cummins or any other brand, these principles apply to all marine diesel engines.

[@BoatLife_DansBoatLife]

Great tip about looking for breakdown vs regular servicing receipts!

[@BoatBuy]

Thanks Dan! Been really enjoying your videos.

[@Jethrosgarage]

Very good points! I used to post profession related videos, but my workplace has some social media policy that basically says anything I say on even my PERSONAL social media policy can be scrutinized.... in any case I have been working on marine diesels since 1985.

[@BoatBuy]

Thanks Jethros! Appreciate the kind words from someone else with a diesel background :-)

[@besearchingforwisdom6267]

This was perfect timing for me as I'm currently shopping for a pair of diesels now. I had a little different set of priorities because most of the engines for sale do not have the options for the first 5 items in your list. Before I take an oil sample, which I agree is critical, is to inspect the blowby and the thrust bearings, then the oil samples. If these are satisfactory, I'll be looking to recondition them for reliability and performance as needed. Replacing the corroded items and resealing them for leaks and servicing the heat exchangers and cleaning and painting them will go a long way toward making the right choices. I'm still shopping Thanks again for your advice and insight

[@BoatBuy]

You're welcome. Make sure if possible you warm the engine up before taking the sample. Is the reason you cannot do 1-5 because the engines are already removed from the boat?

[@besearchingforwisdom6267]

@@BoatBuy Most of engines for sale are already removed and the service history isn't an option, but that would be nice if it was. Nevertheless, before installing anything into the vessel, the work you do first on the bench will be rewarded afterwards. Like I said your insight is very helpful. Thanks again

[@larsl.steffensen1890]

Great video 👍 How to check the turbo, Can that only be done when the boat are sailing. Was trying at the jetty speeding the motor VP slightly up but could not hear the turbo spinn.

[@BoatBuy]

Few different ways to check the turbo. Firstly, listen for any strange noises when it "spools" up. If the turbo doesn't spool up, you'll likely see smoke coming from the engine and it won't perform properly. Lastly, you can check the turbo when the engine is turned off and cold by removing the air filter and feeling for wear. If it's seized and you can't spin it, it's likely got some salt-water inside!

[@larsl.steffensen1890]

Thanks for the information

[@timothycousins4618]

What kind of hours should you expect out of an engine that has been well maintained and does this vary between makes at all ?

[@BoatBuy]

Definitely varies - what you really need to consider is how much HP the engine is putting out VS the displacement of the engine. The higher the HP and smaller the displacement = less time the engine will last. Did you have a particular engine you were curious about and I could quantify for you?

[@timothycousins4618]

@@BoatBuy I am just doing my research before I really get serious about getting a boat which I hope will be in the next year. I won’t have a huge budget so it would probably be an older flybridge cruiser in the 30 to 40 ft range.

[@woodyahh2110]

Boat salesmen hate inspections because what is found out that the owner didn’t disclose and the owner always says they didn’t know Everyone’s a lier when it comes to buying a boat

[@andyhandyman2118]

How to investigate oil samples if oil was changed recently and they didn't tell you?

[@BoatBuy]

Unfortunately there is nothing you can do. Oil samples are only so useful, and in this case they are usually pretty useless - unless there is a major problem that is evident after a short period of running.

[@andyhandyman2118]

@@BoatBuy tnx

[@nixxonnor]

"...as little as a 300 HP Diesel..." What changes when you go even lower than 300 HP? No rules apply?

[@BoatBuy]

In some cases when you go lower than 300hp they don't have things like turbos, after coolers etc which can all have an impact on reliability and life cycle.