onepyramid
Seaman Apprentice
- Joined
- Jun 20, 2014
- Messages
- 35
Here's the situation...our lake has a 9.9 HP limit and a 24' length limit. No huge wakes, no waves, nothing to overcome but 300 acres of flat water and some wind.
Here's the problem...just bought a brand new Lowe 22' pontoon from Cabela's. They have been supplying boats here for years. I specifically told them I wanted a prop that would allow the engine to spin up to normal operating range...a lower pitch unit. They, of course, ignored me and sent the boat with the stock from the factory 10" diameter, 8" pitch, four-blade prop.
Here's the results...engine at WOT will only turn 3100 rpm and it surges like crazy. (It is not just me...Cabela's has delivered five new Lowe pontoons this year, all with the same set-up and all with the same symptoms.)
Here's what they are proposing...To their credit, Cabela's is trying to fix the problem on all boats. They have done two boats already, with one obvious result of eliminating the surging of the engine at WOT. The fix was to exchange the four-blade prop with a three-blade, 10" diameter but with a 9" pitch. However, the maximum rpm now at WOT has dropped to 2400.
Back to my original question....Will restricting these engines to a life of never seeing anything above less than half of the engines maximum rpm cause problems later down the line?
Mercury says this engine has maximum rpm of 6,000. But the Pro-Kicker 9.9 has limited low pitch prop options...the smallest is a three-blade with 7" pitch. Mercury tech says either move back to the standard engine, or have the existing prop re-pitched. I am sure Cabela's will not like either option.
My experience from the past....used to have a two-stroke Mercury 9.9 that plugged the exhaust ports after about four years of operation. Local mechanic diagnosed it immediately as improper pitch prop....he cleaned up the engine, installed a lower pitch prop and the engine spun up and ran like a top for 20 years.
I am trying to avoid this same problem with the new engine, but do not know if similar running conditions for a four-stroke engine are as detrimental. I look forward to your guidance and thoughts.
Here's the problem...just bought a brand new Lowe 22' pontoon from Cabela's. They have been supplying boats here for years. I specifically told them I wanted a prop that would allow the engine to spin up to normal operating range...a lower pitch unit. They, of course, ignored me and sent the boat with the stock from the factory 10" diameter, 8" pitch, four-blade prop.
Here's the results...engine at WOT will only turn 3100 rpm and it surges like crazy. (It is not just me...Cabela's has delivered five new Lowe pontoons this year, all with the same set-up and all with the same symptoms.)
Here's what they are proposing...To their credit, Cabela's is trying to fix the problem on all boats. They have done two boats already, with one obvious result of eliminating the surging of the engine at WOT. The fix was to exchange the four-blade prop with a three-blade, 10" diameter but with a 9" pitch. However, the maximum rpm now at WOT has dropped to 2400.
Back to my original question....Will restricting these engines to a life of never seeing anything above less than half of the engines maximum rpm cause problems later down the line?
Mercury says this engine has maximum rpm of 6,000. But the Pro-Kicker 9.9 has limited low pitch prop options...the smallest is a three-blade with 7" pitch. Mercury tech says either move back to the standard engine, or have the existing prop re-pitched. I am sure Cabela's will not like either option.
My experience from the past....used to have a two-stroke Mercury 9.9 that plugged the exhaust ports after about four years of operation. Local mechanic diagnosed it immediately as improper pitch prop....he cleaned up the engine, installed a lower pitch prop and the engine spun up and ran like a top for 20 years.
I am trying to avoid this same problem with the new engine, but do not know if similar running conditions for a four-stroke engine are as detrimental. I look forward to your guidance and thoughts.