Hard starting

Hello,
I have an old 70s Volvo Penta 90 2-cycle that I have been working on. I have her running pretty well but she is hard to start. With a small 12 volt jump-battery (or a 12v deep cycle) she is hard to start but if I hook the batteries up in series (24v) the starter turns quickly and she starts much more reliably. I can only rarely pull start her. Once she is started and warmed up for a minute (she often stalls the first few starts) she idles perfectly and revs well.

Reeds looked good. Carb has been thoroughly cleaned x4 times. New carb/manifold seals. Compression was 64/60 with hand pull, ~90 with 24v starter.

Any suggestions what I should do it to make her start more easily?

Thanks!

Re: Hard starting

i once had that problem with my 90 hp force, i could have bought a new starter for $250 or had mine rebuilt for $225 so i took the starter apart and it was very dirty inside, water corrosion and stuff i never seen before. anyways i cleaned it up used emery paper on the copper part of the rotor where the brushes touch and cleaned and sanded all the connections... so either taking your starter apart or buying a new one or getting it rebuilt may help you. just my thought.

Re: Hard starting

Your compression readings are very low.Most two cycles require AT LEAST 100 psi to reliably start and run well.May be time for new rings or crank shaft seals.Squirt a little oil into the cylinders and with the throttle wide open see if your compression readings increase.