Top Speed Drop

[Johanv09]

Hi everyone!

I have had my AR220 for 2 years. The first 5-6 months, the boat took a max speed of 39 MPH with 8 people on board. Since last year, we can barely take 34MPH, WOT @ 7,200 with 5-6 people. The dealer said that everything is fine, they could not find any issue. I boat around Tampa Bay Area.

Has anyone had this issue before? Any advice will be highly appreciated. TIA.

 

[lazergeek]

Your not getting full RPM's. Make sure your oil is not oeverfilled first, it should be between the 2 lines, not over the top line. If thats fine then replace your spark plugs. my RPM's always drop when the plugs need replaced. AfterI repalce its immediatly resolved.

 

[Neutron]

Your not getting full RPM's. Make sure your oil isnot oeverfilled first, it should be between the 2 lines, not over the top line. If thats fine then replace your spark plugs. my RPM's always drop when the plugs need replaced. AfterI repalce its immediatly resolved.

I second the plugs

 

[Babin Farms]

Plugs and oil would be the first things to check like @lazergeek mentioned. Do you trailer, dry stack or wet slip? Have you felt the hull that normally sits in the water? Is it nice & smooth or does it feel rough? A dirty hull will reduce top speed.

 

[Johanv09]

Plugs and oil would be the first things to check like @lazergeek mentioned. Do you trailer, dry stack or wet slip? Have you felt the hull that normally sits in the water? Is it nice & smooth or does it feel rough? A dirty hull will reduce top speed.

I trailer my boat and keep it in a dry storage. I don’t think that dirty hull is not the issue because I clean and detail the body every day I take it out of the water. The hull feels so smooth like new!

 

[Cobra Jet Steering LLC]

Be sure you do not have an exhaust leak in the engine compartment like a broken clamp on an exhaust hose , another thing to check is your air cleaner element.

 

[FSH 210 Sport]

What rpm’s were you getting when it was going faster?
What were the conditions? Air and water temperature?
Did this change happen right after a service ?
Have the spark plugs been changed since new?

Like the others I say check your oil level, follow the procedure in your owners manual, and be sure to screw the oil dipstick in fully when checking the oil level! If you don’t this will lead to an overfill in the oil tank.

When installing new plugs be sure to check the gap (.028”-.032”) before installing them to make sure they’re within specification.

The port engine turning more rpm than the starboard is normal as the impellers are the same pitch for each side and the starboard side gets more load than the port side.

If the oil level and plugs don’t correct the issue check the air cleaners, you might even check the air boxes clean and pull the filters to see if that makes a difference, if it does put in a set of RIVA racing oiled gauze filters, in my situation the RIVA filters resulted in a 150-200 rpm increase.

 

[tdonoughue]

Others have suggested the first things.

On the list on next things to check would be impellers and the intake path. Nicks in the impeller and non- smooth intake paths can cause cavitation that can drop top speed. Normally with cavitation one expects increases in rpm, but without knowing the exact rpm before under the same conditions, that may be hard to determine. Worth a check imho.

 

[jcb1977]

Your not getting full RPM's. Make sure your oil is not oeverfilled first, it should be between the 2 lines, not over the top line. If thats fine then replace your spark plugs. my RPM's always drop when the plugs need replaced. AfterI repalce its immediatly resolved.

my experience with the TR-1's is you actually want to be less than halfway full with the oil......about 25% up from the bottom line to get max RPM's.