Prop Question

[QBhoy]

Injected, yes. The carbed engines don't have a rev limiter. It will run as fast as the prop allows it.

Chris......

You’re wrong on this Chris. I certainly know of a 4.3 carb that has an rpm limiter.

 

[achris]

You’re wrong on this Chris. I certainly know of a 4.3 carb that has an rpm limiter.

OP has a '93 4.3LX. That's TB-IV, and TB-IV has no rev limiter....

 

[QBhoy]

OP has a '93 4.3LX. That's TB-IV, and TB-IV has no rev limiter....

Ok. So genuine question coming up here...

I can technically understand the thinking here and my head wants to agree that there is nothing from stopping a carb 4.3 from limiting..but 100% I know of a 1999 4.3 carb that limits and pops right on about 5000 rpm. What would cause this 4.3 to limit ? Is it governed by a crank sensor ? Not sure I know of a carb with a crank sensor on it...but for sure this 4.3 limits at those rpm. Also known a 95/96 boat with a 4.3 to also do it. What would determine this ?

 

[achris]

Ok. So genuine question coming up here...

I can technically understand the thinking here and my head wants to agree that there is nothing from stopping a carb 4.3 from limiting..but 100% I know of a 1999 4.3 carb that limits and pops right on about 5000 rpm. What would cause this 4.3 to limit ? Is it governed by a crank sensor ? Not sure I know of a carb with a crank sensor on it...but for sure this 4.3 limits at those rpm. Also known a 95/96 boat with a 4.3 to also do it. What would determine this ?

'99 carbed has a TB-V, and some have a limiter. They do it just by pulse timing (to determine RPM) and they stop every second spark, so as not to suddenly shutdown the engine. Not a good look when traveling at 30+ knots and the engine suddenly stops producing all power. All the things in the back of the boat (including people) are transferred to the front.. Ask anyone with the early Johnrude outboard with the 'S.L.O.W' feature.... OMC changed the feature to be a 'slow S.L.O.W.', when the overheat was detected, the engine slowed down slowly, not all of a sudden.

As for your '95/'96 boat, mid-1996 was when the V6 transitioned from non-vortec to vortec, and with that also TB-V, so it may be that this engine is also TB-V but certainly, TB-IV never had a limiter.

Chris......

 

[QBhoy]

'99 carbed has a TB-V, and some have a limiter. They do it just by pulse timing (to determine RPM) and they stop every second spark, so as not to suddenly shutdown the engine. Not a good look when traveling at 30+ knots and the engine suddenly stops producing all power. All the things in the back of the boat (including people) are transferred to the front.. Ask anyone with the early Johnrude outboard with the 'S.L.O.W' feature.... OMC changed the feature to be a 'slow S.L.O.W.', when the overheat was detected, the engine slowed down slowly, not all of a sudden.

As for your '95/'96 boat, mid-1996 was when the V6 transitioned from non-vortec to vortec, and with that also TB-V, so it may be that this engine is also TB-V but certainly, TB-IV never had a limiter.

Chris......

Ah. That makes sense Chris. Fair play and appreciate the explanation. I never tire of being educated on here and like to think I’m humble enough to know when to ask for explanations such as this. Thanks again.

Ps. Still think I’m right about the diz cap failure issue on the MPi though, haha. Cheers again !