Bayliner BR175 year 2004

How to repair broken bolt on boat starter motor

The engine would not start. See video here

Reason was a broken bolt holding the starter engine.

Seen from above after starter motor got removed:

We cut a notch in the broken bolt from above by using a battery driven drill with a Dremel EZ SpeedClic SC406:

We tried with a regular screwdriver, but without any luck.
We tried with an impact screwdriver, but without any luck.

We drilled a 2.5mm hole, but it did not get accurate enough due to the thick engine block and lack of space to get the drill straight

Hole was offset by 4mm at the bottom, which was not accurate enough.

We then got hands on an induction heater 'Alesco A80' - a VERY powerfull tool!!!

It can heat up a 10mm nut until it gets red! (testing it before using it on the boat engine)

After heating the broken bolt a lot, and using anti-corrosion on it, we still did not succeed to turn it when trying with an impact screwdriver.

But we did succeed turning it with a standard screwdriver!!!

We had to turn it within 20 seconds after removing the induction heater. After 20sec it got stuck again.
Heating, turning a bit, heating, turning a bit, heating, turning a bit, ... and so on for 30 minutes, and the broken bolt got out!

The broken bolt was actually quite long. No wonder why it got so stuck in the engine block after living 15 years on a boat...

The starter got re-assembled with two new bolts, and the engine now starts perfectly again.

Mission accomplished :)

Last modified 2021-04-24 @ 20:33