Boat engine goes out of control on first test run
Hansen Boatworks Hansen Boatworks
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 Published On May 8, 2023

**UPDATE AND CLARIFICATIONS IN DESCRIPTION BELOW**
We're running a replacement engine (a 1975 SABB diesel) for the first time during a rebuild. Things go badly, we're forced to replace several parts, and investigate the cause. We cannot proceed with the refit of Nibiru unless this engine runs properly! Subscribe to follow our progress on this journey!

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Update and clarifications:
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Hey all, so we didn't think this would blow up like it did, but here we are. Really appreciate you all coming to watch our blunder, it has been a lot of fun. We wanted to take the time to elaborate / respond to sentiments we've been seeing more than once:

"Don't quench the copper! It hardens!"
The old guy has been annealing, quenching, working metal professionally for over 30 years, and as a hobbyist for nearly another 30. We know all about it, this is very far from the first time he has annealed metals. Annealed copper can be cooled in water just fine, it was still soft, and the seal is currently perfect. The engine has been run repeatedly over the past couple months without a singular sign of leakage. The quench in the footage is not a necessary step to the process, but in that moment we simply wanted to get on with it, so we cooled it quickly. We may not be paragons of engine safety 🤣 but he does know his metals.

"You say that, but the head gasket is clearly still leaking, it's right there in the video!"
Nope, the head gasket is sealed perfectly. The footage is catching tiny puffs of exhaust coming from the fuse socket just above the head gasket (it was a little loose). Also there is steam from the water cooling intake boiling over between cuts. The steam is being fanned around by our salvaged air cooling flywheel. Sorry we didn't clear that up.

"You call that a rebuild? The thing is filthy!"
So the video could have been worded A LOT better, that's our bad. What you're seeing leading up to the big event is a rebuild at 90%, and us making some dubious assumptions by running her. The engine at present is clean, painted, beautiful, and like we've said: has been running in the shop once or twice a week just for fun :) There will be more footage coming before we install her in the sailboat.

"... Okay well, what did you do up until this point?"
and "where did this engine come from? What state was it in?"
Sadly we started filming at the end of the rebuild, we would have loved to show the process leading up to the test runs.

This engine was a basket case we were given through friend, she came out of a derelict sailboat, the make and size we don't know. We are actually not the first to attempt rebuilding this engine, as it passed through several hands that gave up on it, ultimately.

After it arrived in our shop the rebuild process (before this video) involved:
1) Assessing the work done by previous owners (was chaotic to say the least).
2) Reseating the head valves.
3) Replacing the transmission.
4) Pulling the piston, cleaning up the parts.
5) Installing a new flywheel. (Harvested from an air cooled engine we had lying around.)
6) Cleaning the ancient tar-like oil out of every little nook.
7) And last but not least: Repairing a giant crack in the block.

"What was the cause?"
The cause was a malfunctioning governor, with an incorrectly assembled fuel injector compounding the issue. We have since determined that the fuel injector documentation was in error. We attempted to corroborate the information online, but we were unable to clarify the situation as our time scouring the internet produced incorrect information as well. The fuel injector was providing at least 2x the necessary fuel. In the strictest sense, this wasn't a diesel runaway as it wasn't being provided an unintended fuel source. But the supply of fuel was beyond out of control.


Thanks for checking our video out guys! We hope that clears some stuff up. It really is a shame the filming process didn't start sooner, but we felt like we wanted to scrape something together and get it up just to share in our learning process. This video is as much a lesson of what not to do as anything.

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This is video 2 in Nibiru's Refit project, playlist here:    • Nibiru Sailboat Refit Series  

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Corrections:
00:08 - This was incorrect. At the time of the this recording the engine was not done being rebuilt. This was the result of a miscommunication between editor and shop, sorry about the confusion. We're going to do a better job in the future. See the description for more.
01:14 - Since uploading we determined this was not a diesel runaway as the engine was not being provided an unintended fuel source. The the problem was with the governor. Additionally, the fuel injector was also assembled incorrectly following incorrect original manufacturer instructions. As a result we estimate the injector was providing at least 2x the necessary fuel.

#boatengine #sailboatrefit

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