what is a Rev Limiter?

[jkust]

I have a 2003 4.3 Mercruiser carb pushing my Chaparral. It turns over 5000 rpm with the oem 21p alum prop but the max rpm range is 4850 (if I recall). I always hear about the "rev limiter" in posts but not mention of how it works. Does this engine have a rev limiter? If so what does it do and when should it do it? I am realizing I have enough RPM's to go up a pitch. I actually hit 52mph on the gps this week not at wot but at about 4850 since I finally got to drive without the whole family on a quarter tank since we stayed at the resort. To me 52 is fast since the Chap is such a tank, the prop is less than desirable and holds 35 gals compared to most same sized br's.

 

[Bondo]

Re: what is a Rev Limiter?

Ayuh,... I don't know if your motoris equiped with a Rev Limiter or Not...
Some of the T-Bolt V igntions do,.. T-Bolt IVs do Not...
If so, it'll drop a cylinder or 2 at around 5000/ 5200rpms...

Most boats use the Prop as a Rev Limiter,...
So prop it to 4800rpms,+ you'll have Nothing to worry about...

 

[dontask]

Re: what is a Rev Limiter?

I have a 2003 4.3 Mercruiser carb pushing my Chaparral. It turns over 5000 rpm with the oem 21p alum prop but the max rpm range is 4850 (if I recall). I always hear about the "rev limiter" in posts but not mention of how it works. Does this engine have a rev limiter? If so what does it do and when should it do it? I am realizing I have enough RPM's to go up a pitch. I actually hit 52mph on the gps this week not at wot but at about 4850 since I finally got to drive without the whole family on a quarter tank since we stayed at the resort. To me 52 is fast since the Chap is such a tank, the prop is less than desirable and holds 35 gals compared to most same sized br's.

When you say that you hit 52 mph (GPS) did you also measure the boat speed going the opposite direction to factor out the water current and wind conditions you were in?

 

[towman818181]

Re: what is a Rev Limiter?

its just what bond-o says its designed to keep you form over reving your enging and causing internal damage

 

[jkust]

Re: what is a Rev Limiter?

When you say that you hit 52 mph (GPS) did you also measure the boat speed going the opposite direction to factor out the water current and wind conditions you were in?

Well yes believe me I did since it was the first time I could just play around without the whole family since buying last season. It was a lake so there wasn't much perceivable current and the wind was maybe 8-10 mph. Speeds ranged from 46 mph to 52 mph but the 52 mph was going perpendicular to the wind not with the wind. I was shocked to see 52 on the gps since that is 6 mph faster than fully loaded. Also, it is the first time I was able to cruise with the center window open for whatever that is worth. It is a Thunderbolt V and I can't really see this engine having a management component. It is pretty primitive.

 

[pinecrestwoods]

Re: what is a Rev Limiter?

I used to work on bikes a fair amount and my cousin came to me with his Shadow, saying, "When I really get on it, the dang thing cuts out.... I think it's starving for fuel!" Well, no..... your bike's a v-twin, you were hitting the rev limiter and it was cutting out.... hmmm... problem solved. Stock twins don't turn 10k!!! They're there for a reason- as a LAST resort, and my boat doesn't have one, at least I don't think so. I also need to change my prop someday.

 

[Bondo]

Re: what is a Rev Limiter?

It is a Thunderbolt V and I can't really see this engine having a management component. It is pretty primitive

Ayuh,... There's a pretty sophisticated little bitty black box mounted near the distributer that controls the Spark, Timing,+ has provisions for being a Rev. Limiter...
Sometimes the T-Bolt V's use a Knock Sensor to cut the timing in case of detonation....
It seems the Rev Limiter,+ Knock Sensor are optional,...
I know some motors with the T-Bolt V don't seem to have Either,+ others have Both....