2007 210 Outrage VERADO 200 In-line Six-cylinder

[lewain]

i have a 2007 210 Outrage with a fiberglass T-Top, powered by a Mercury 200 Verado six-cylinder and turning a REVOLUTION4 17-propeller. I am not really concerned with the [fastest boat speed]. At full-throttle the VERADO 200 accelerates to 5200-RPM.

I was always told that the propeller [should be chosen to allow the engine speed at full-throttle] to get close to the manufacture’s engine speed RPM rating.

The REVOLUTION4 propeller has [all the propeller hub vent holes plugged].

Q1: would removing one vent plug or all vent plugs help increase the engine speed at full throttle?

I live on a lake and have run the 210 OUTRAGE boat on the water when it looked like glass. And I have been offshore in the boat, and the engine speed at full throttle has never been greater than 5200-RPM.


Q2: should I get a different propeller?

Q3: between a three-bladed or a four-bladed propeller, which should I get?

Q4: what propeller would YOU try?

[fno]

I would avoid for now the analytics and expense of trying different propellers.

I, too, have a 210 Outrage with a T-Top, but with a Mercury FOURSTROKE 225 (using the Yamaha powerhead) engine mounted one-hole-up. The propeller is a MIRAGE 19-pitch. [Probably the MIRAGEplus model.]

The full-throttle engine speed with the engine trimmed all the way in is 5200 to 5300-RPM. The YamaMerc 225 will not accelerate to anywhere near 6000 or 6100 until the engine is substantially trimmed out after the boat accelerates to planing speed.

The top boat speed with a light load is between 48 and 49 MPH statute.

Don't pull the plugs [in the propeller hub vent holes]. They are a gimmick.

[jimh]

Q1: would removing one vent plug or all vent plugs help increase the engine speed at full throttle?

SHORT ANSWER: No or very unlikely.

LONG ANSWER:
Regarding Mercury propellers with vents in the propeller hub, Mercury calls that feature the “Performance Vent System” and uses the acronym PVS.

For boats with a top speed potential of greater than 60-MPH in which the propeller pitch will be 24-inches or greater, the use of the PVS plugs with some small vent holes in the plugs MAY help the engine accelerate better while trying to get the boat onto plane by acting as a spoiler to the propeller getting a solid grip on the water by venting engine exhaust gases out of the hub and onto the working surfaces of the propeller blades, which will then be spinning in less dense aerated water reducing the load on the engine.

Once the boat speed increases, almost all exhaust gas will resume to venting from the main hub opening, and the open vent plugs will not make as much or in some case will not make any difference on the load created by the propeller on the engine. The propeller load on the engine is what halts the acceleration of the engine to greater engine speed.

Also, the plugs are NORMALLY changed in all ports in unison steps, typically testing with NO HOLE (or NO venting at all), and then testing with all holes changed to plugs with small holes, followed by medium holes, followed by large holes. Going to NO plugs at all is an extreme case. Going to ONE vent completely open and the rest completely closed would not be likely to be useful. The propeller blades will have different amounts of grip, which will likely induce vibration.

If you want to fiddle with PVS plug holes sizes, just buy a new set of full plugs. Then start testing, beginning with the existing full-sealed plus, then drilling progressively larger vent holes in the plastic plugs and testing over and over as you drill larger holes.

But all that nonsense is really of no value unless you are aiming for 75-MPH and want to get there 5-seconds faster.

For the typical Boston Whaler moderate deadrise, moderate planing-speed boat that maybe gets run at full throttle on rare occasions and hits 40 to 45-MPH, I don’t think the PVS plugs would ever make the engine work better by setting them to be opened (venting).