jbizub5192
New member
Hi Everyone,
Im working on a friends boat, this is my first Yamaha as Im used to Mercury. Its a 96 40hp 2 stroke. I believe the rpm range should be between 4500 & 5500? Ideally I would like to be around 5k. Right now its maxing out at 3900. This engine is on a 18ft sweetwater pontoon boat. The boat itself is pretty light. It has a current prop of 10 5/8 x 12 which looks to be an oem Yamaha prop. At first I was thinking the prop was too big. However upon looking, this already seems to be a small prop and shouldn't have any issues getting it up to max rpm. Can someone give their opinion on that? If that assumption is correct then my next step is trying to trace down the issue. Will probably start with a carb rebuild and fuel pump rebuild. The engine is currently running absolutely fine other then not achieving max rpm. I know the previous owner put a new lower unit on as it was damaged by a stump I believe. I know on inboard outboards the lower units have different gearing that can be changed. I don't believe that is the case with most outboards. That was by only other thought is if the gearing was different.
Thanks for the assistance,
Justin
Im working on a friends boat, this is my first Yamaha as Im used to Mercury. Its a 96 40hp 2 stroke. I believe the rpm range should be between 4500 & 5500? Ideally I would like to be around 5k. Right now its maxing out at 3900. This engine is on a 18ft sweetwater pontoon boat. The boat itself is pretty light. It has a current prop of 10 5/8 x 12 which looks to be an oem Yamaha prop. At first I was thinking the prop was too big. However upon looking, this already seems to be a small prop and shouldn't have any issues getting it up to max rpm. Can someone give their opinion on that? If that assumption is correct then my next step is trying to trace down the issue. Will probably start with a carb rebuild and fuel pump rebuild. The engine is currently running absolutely fine other then not achieving max rpm. I know the previous owner put a new lower unit on as it was damaged by a stump I believe. I know on inboard outboards the lower units have different gearing that can be changed. I don't believe that is the case with most outboards. That was by only other thought is if the gearing was different.
Thanks for the assistance,
Justin