Blue smoke at higher RPMs from Universal M40

[Pete the Cat]

I am not sure what engine you have, but Yanmar mounts are different, and for a reason. There is a lot of vibration in any small diesel and Yanmar engineers say they designed their mounts (which have a unique W shape) to allow the engine to vibrate more so as to not transfer that to the bed and hull of the boat. Yanmars can look like they are trying to take the drive train out of the boat at low RPM when they are perfectly aligned. You also might check all the nuts (top and bottom) on your new mounts; I have forgotten to tighten one occasionally when I was younger (surely would never do that today). They all (8) need to be snug when you finally get it set right. The last thing you check is the gap at the coupling for the 50th time.

 

[EricFox]

By way of an interim follow-up, I added Lucas oil stop leak when I changed my oil in September on the advice of several who suspected worn value stem seals or worn piston rings - no change to the smoking above 2k RPM. But as I was preparing to haul out for the year, the local diesel mechanic happened to be in the marina so I showed him first hand what I was seeing. His immediate reply was dirty fuel injectors - he thinks it's running too rich at WOT, not burning oil. I'll update in the spring when I'm back in the water and have swapped out fuel injectors.

On that topic, any advice on having my existing injectors cleaned and refurbished versus replacing with new?

BTW, the old injectors are stamped with a part number 1570-50 (looks like Nippon Denso). An older set that I have from a previous owner are stamped 1570-12C. The engine stamp is V1501. Based on other posts, if I opt for new then I think what I need is Kubota part number 97898-20530 (Kubota L345 tractor) based on this post https://ericsonyachts.org/ie/threads/universal-5432-m40-engine-information.10241/.

I'll update in the spring when I'm back in the water and have swapped out fuel injectors.

 

[Frank Langer]

By way of an interim follow-up, I added Lucas oil stop leak when I changed my oil in September on the advice of several who suspected worn value stem seals or worn piston rings - no change to the smoking above 2k RPM. But as I was preparing to haul out for the year, the local diesel mechanic happened to be in the marina so I showed him first hand what I was seeing. His immediate reply was dirty fuel injectors - he thinks it's running too rich at WOT, not burning oil. I'll update in the spring when I'm back in the water and have swapped out fuel injectors.

On that topic, any advice on having my existing injectors cleaned and refurbished versus replacing with new?

BTW, the old injectors are stamped with a part number 1570-50 (looks like Nippon Denso). An older set that I have from a previous owner are stamped 1570-12C. The engine stamp is V1501. Based on other posts, if I opt for new then I think what I need is Kubota part number 97898-20530 (Kubota L345 tractor) based on this post https://ericsonyachts.org/ie/threads/universal-5432-m40-engine-information.10241/.

I'll update in the spring when I'm back in the water and have swapped out fuel injectors.

I took my injectors to a specialty shop years ago. He was able to clean one of them to get the flow pattern corrected, but he suggested the other one be replaced at a cost of about $50 eight years ago. I would trust the opinion of a similar specialty shop.
Frank

 

[Loren Beach]

When I took the injectors in for servicing on our former Universal M25XP, they replaced the tips because the spray pattern was not as it should have been.
When reinstalling, do use new crush washers and a torque wrench to tighten them to exact spec.

 

[EricFox]

When I took the injectors in for servicing on our former Universal M25XP, they replaced the tips because the spray pattern was not as it should have been.
When reinstalling, do use new crush washers and a torque wrench to tighten them to exact spec.

Thanks, Loren and Frank - there a fuel injector refurbisher nearby - I'll start by taking them there.

 

[Christian Williams]

I agree. Fuel injectors testing and correction is widely available, even by mail order. Mine tested OK, new tips were $50 each.

Removing them is a job we can do ourselves, and others have reported new injectors to be close to the cost of cleaning and correcting. Worth a comparison and an open mind.

Trouble is, my injectors were actually fine and engine improvement was psych only. But you never know that until taking them out.....

E381 - Fuel Injectors Service

Small diesels are renowned for their simplicity. They have no ignition system and in a pinch they'll run on cooking oil. Diesel fuel doesn't aspire to be napalm, and unlike gasoline feels almost natural on the skin. Diesels work forever with...

ericsonyachts.org

 

[Frank Langer]

I agree. Fuel injectors testing and correction is widely available, even by mail order. Mine tested OK, new tips were $50 each.

Removing them is a job we can do ourselves, and others have reported new injectors to be close to the cost of cleaning and correcting. Worth a comparison and an open mind.

Trouble is, my injectors were actually fine and engine improvement was psych only. But you never know that until taking them out.....

Some diesel repair books (eg. Nigel Calder) suggest injectors be serviced every 900 engine hours. However I recently spoke with a diesel mechanic who said if my engine starts easily, runs well, doesn't smoke, etc. then it's reasonable to assume the injectors are ok.
Frank

 

[EricFox]

Just got a quotation of $C 257 each (around $188 US) from the local Kubota dealer - I'll definitely try the refurb route first!