max real rpms

[secretary of the marsh]

I've got a 1992 merc 40 that has a max rpm of 5500. I run it on an old 1648 jon. How far over that can I go, realistically, with me and no gear?

 

[86 century]

Re: max real rpms

As high as will go till it comes apart.

If it will rev past the manufactuers recomended max you need a higher pitch prop.

 

[Laddies]

Re: max real rpms

The 44 cu. in. 4 cyls are run in D stock runabout in the 7000 RPM range

 

[Sprky]

Re: max real rpms

HP starts falling off quite quickly after 6000 unless the motor is modified.

Let it eat.... the motor will tell you what it wants.

Six

 

[Laddies]

Re: max real rpms

D stock runabout is a factory stock engine and don't fall off till 7000+ that don't mean it's a recommendation, just a fact.

 

[sschefer]

Re: max real rpms

D stock runabout is a factory stock engine and don't fall off till 7000+ that don't mean it's a recommendation, just a fact.

Absolutely true fact! You need to make sure you're jetted correctly so you don't risk leaning it out but yes, it will do 7's. For longevity you would probably want to stay in the 5800-6000 range though. I'm of the opinion that Merc feels 5500 is a safe max to ensure the motor makes it through the warranty period.

 

[Sprky]

Re: max real rpms

D stock runabout is a factory stock engine and don't fall off till 7000+ that don't mean it's a recommendation, just a fact.

\\

I wasn't referring to D stock motors. With that being said, the vast majority of mercury's have great over-rev potential even with the hp falling off.

The 260's and 300 drag motors will spin into the high 10's low 11's with the right changes, but they make max hp in the low to mid 9's

Are you sure the D stock motor is the same block as the 92 40 hp? I thought the 44ci motors were the merc 500 from the 60's and the classic 45 and 50 thru the late 80's. Isn't the 92 40 hp a totally different block?

Do you race laddies, or just spectate?

Steve, why would you need to jet up? Why would x jet be ok at 5500 but not at 7500. Maybe you could school me.

You should look at the fuel map of a motor that can actually spin up! You might change your mind.

 

[Laddies]

Re: max real rpms

The 1992 powerheads are approved for D stock by APBA. I have had engines win 5 National Championships in D' so I guess that would answer do I race. No but my kids do.

DO YOU RUN ANYTHING BUT YOUR MOUTH Sprky?

 

[Sprky]

Re: max real rpms

Actually Laddies I have 3 High points and 3 "World" (lol) Outboard drag championships. I have wrenched for others and I have driven for others. I even got paid to drive for a guy one season, but looking back I got the short end of the stick.

I also have an "I love me" room with somewhere between 70 to 85 trophies and placs of various places, but that is yesterday's news and not worth "spit".

The great thing about the internet is there is no voice inflection.

There was never any malice intended. But you turned it that way.

This is my last ride Laddies, How about you?