Brain fart: are they interchangeable?

A mate has a B20-powered boat and needs a starter motor for it.

TIA.
I put a B21 starter into my B230FT because I like the sound of the older starters. Plus mine was failing.
Spac, I have a minimal use reco'd starter motor from a B21 that I removed just before I got rid of the car (back in 2001).
its been sitting in a box ever since being removed. I think it was only on the car for 3 months or so.

Its yours if you pay for the postage.
You're a good man, Ash. I'll speak to Andrew tomorrow and see if he's keen (he bloody ought to be!).
I'll dig it out tonight (ie. confirm it is where I think it is) and post a couple o pics if you like.
Spac. I just dropped you an MMS with a pic (assuming you still have the same mobile number.)
Starter is stamped with
Bosch 0 001 311 103
25 days later
I can confirm that B20/B30/all redblock starters interchange, I put one from a B20 on my 242 with B23 many years ago, back when there were rows of 100 series cars in Pick-A-Part.
9 years later

Yes you can mount a 2 series starter in a 1 series B20 motor , you may need to over size one of the mounting holes from memory.

It's been decades since we did it.

One other difference is some starters have an extra terminal, on early K-Jet cars it connects to a brown wire. The brown wire powers the coil while the starter is cranking and bypasses the ballast resistor that the blue (switched +12V) wire runs through. I assume this is to give a stronger spark while cranking or something but I don't really know. If your car has that brown wire, you can disconnect it, just wrap the unused terminal in some electrical tape as it will have +volts on it when the car is running.

    yeah they fit, you just have to drill out to M12

    jamesinc

    One other difference is some starters have an extra terminal, on early K-Jet cars it connects to a brown wire. The brown wire powers the coil while the starter is cranking and bypasses the ballast resistor that the blue (switched +12V) wire runs through. I assume this is to give a stronger spark while cranking or something but I don't really know. If your car has that brown wire, you can disconnect it, just wrap the unused terminal in some electrical tape as it will have +volts on it when the car is running.

    Isn't that the wire to trigger the cold start valve, via the thermal time switch or some such on kjet cars?

    Some starters have thru-holes and bolts with nuts...some have threaded holes for the bellhousing bolts. I believe the earlier cars had thru-holes, and later had threaded holes.