New to me 1991 Commander jet boat is difficult to start. Replaced batteries yesterday and it takes both batteries to turn the engine over. Shouldn't it start on one battery? Brand new Exides. Engine is 454 with 9.5:1 compression, so it's not a really high compression engine.
Any ideas/suggestions where I should start looking?
I would pull the spark plugs out ,turn it over with a long ratchet/torque wrench on the crank bolt and see how it feels.
note on the Torque wrench when it clicks.
Just wondering what would be the normal torque required to turn over a big block? Never thought of checking it, but I would think that things like valve springs, ring type etc.... would play a roll as well.
mine was doing same thing last year. I put a new starter in it and fixed problem. i dont suggest a rebuilt from autozone, but if you do ask for one from a 72 chevelle 454. they were higher compression engines and starters had more torque. also I use plugs from same year car seems to be hotter spark than later model smog 454. the engine gurus would know more.