Can anyone help me fix a seized engine?

euser1984

It's a new engine for a Baja 5B (Fuelie 26cc petrol)(started and confirmed to be working a few times when I got it first), it has been sitting in the shed since last winter.

When I start to pull the starter the piston doesn't move. If I pull it any further I think the cord will snap. I tried taking the spark plug out but no joy there either.

Can anyone help here?
Thanks.

T-Maxx

First off I've no experience with that specific motor but I would suggest heating the block with a heat gun and gently pulling on the pull starter. You are right - pull start cords do snap fairly easily so don't go all out on it. You could also damage the conrod if you force things too much. Maybe a bit of WD40 on top of the piston and letting it soak a whiule may help some - it could alse be rusted and not seized. If it stays stuck though you'd have to see if you can get access directly to the underside of the piston.

If it was mine I'd pay close attention to the condition of the rings, sleeve and bearings.

peter bermingham

you can get rebuild kits for them have a baja 5b meself their not that hard to fix its a fairly simple engine http://www.mmrlargescale.co.uk/ all ya have to do take of the head then the cylinder block is held on with two bolts get that of on with new piston check barrel for bad scratches you could give it a rub with 1200 sand paper you cant take out deep marks the sanding is only to smooth out any grit or light marks ya can download the manual for them if you get stuck you should mix the fuel 25:1 5000mm petrol to 200mm of oil castrol tts i think its called is a good twostroke

euser1984

Got this one sorted - it was actually the dyno magnet scratching against the disk that the pull starter spins.

Thanks for the replies though