Re: Slow going....

Posted by Ken Sadler On 2013/3/1 14:20:16

I worked out that the starter motor should spin at about 2500rpm in order to turn the engine at, say, 250rpm - enough for it to start.

Well I've checked the starter motor again on the floor and I'd say is it spinning at about 300-500 rpm, so there's my problem.

Now I'm not sure if its an issue with the starter motor itself or the new battery I just bought, although the old battery was just about the same.

The motor turns freely enough and all 4 brushes have meat left on them and they seat on the commutator nicely with pressure from the springs.

A thought on the battery though. The book says that the 745 should have a 160Ah battery. The one I've fitted is 120Ah (its the biggest one that would fit in the box!)

The capacity in Amp-hours should be irrelevant to the cranking power. Thing is, with these traditional 6volt batteries, no cranking power rating is given.

Any thoughts?