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Message board > Engines > RPM on Volvo 203HP 4.3l

Message 2 of 2
Posted by member Calum Norris on Wednesday 28 September 2022

Hi there, I had the omc 4.3Ltr v6 in my last boat. Basically they are gm units used by most manufacturers. Mine would rev easily to 4800rpm and speeds of 40 plus in what was a very heavily built boat (picton 20ft) much heavier than mr current Hardy FP 20. Without knowing your set up it sounds that you are being limited by fuel, either mechanically on linkages or by starvation. Mine was a 205hp and had a four barrel carb. If yours is similar I would suspect that the secondary barrels are not coming in as they should so you are running on the primary barrels only. These carbs are easy to strip and service so may be worth doing. Hope this helps.

Regards Calum

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Message 1 of 2
Posted by member Colin Caldicott on Wednesday 28 September 2022

I have a newly rebored unit of the aforementioned engine in my Seawings 254. I have done a compression test and have 180+psi from each cylinder. So that seems ok. I have new set of Bravo 3bladed props 20/21inch exactly as the old ones. Engine starts well and runs like a sewing machine.
However, Wide Open Throttle will only give me 3,000 rpm (This is exactly what I had with the old block) and a top speed of 20 knots
I can live with 20 knots, cruising at 16 but am concerned that with the 3000 rev limit it is causing wear to the engine

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