350 mags won’t rev past 4000
#1
Thread Starter
Registered
Joined: Nov 2020
Posts: 13
Likes: 0
My 89 272sr1 with twin 350’s wont rev past 4000rpm. It has 23p Laser 2 props on it. The boat does 37mph @3000rpm
44mph @3500rpm and 50mph top speed @4000rpm. I remember the boat revving higher when i first got it. I think it’s strange that both engines are doing it. I don’t think I’m over propped. I read about plenty of people revving to 4800 with 23p props. My props have some small dings in them but nothing serious. The boat runs great. All fluids were just changed. So my question is, what could get going on other than being over propped?
44mph @3500rpm and 50mph top speed @4000rpm. I remember the boat revving higher when i first got it. I think it’s strange that both engines are doing it. I don’t think I’m over propped. I read about plenty of people revving to 4800 with 23p props. My props have some small dings in them but nothing serious. The boat runs great. All fluids were just changed. So my question is, what could get going on other than being over propped?
#3
Thread Starter
Registered
Joined: Nov 2020
Posts: 13
Likes: 0
#5
Registered

Joined: May 2009
Posts: 627
Likes: 408
From: Indiana
Does seem strange that they both do it. That would make me think of a linkage problem. Carbs,or throttle body, not being pulled to full open.
Don’t know what kind of ignition you have but also need to verify you are getting timing advance as RPM increases.
Don’t know what kind of ignition you have but also need to verify you are getting timing advance as RPM increases.
#6
Thread Starter
Registered
Joined: Nov 2020
Posts: 13
Likes: 0
i have a thunderbolt ignition. I pushed the lever all the way forward and there is about a 1/2” left of cable travel so it seems that the carb itself is going full throttle



