Long story, but here goes.
Bought Mako 18LTS with 115 Optimax 2 cycle back in late 2014. The motor had generally run pretty well. I do take it down to the NC coast and get in some fairly shallow water that has some grass and I'm sure I have skimmed the bottom a few times. Last September (2020), I was running at high rpm's and got some tones and the engine dropped down to idle or somewhere in that range. I took it in and was told the problem was the water pump as it had never been replaced. They acted as if it was common to need to replace the water pump every 2-3 years if running inshore down at the coast. So, the water pump/impeller was replaced, I fished some more last fall through this July in Lake Norman in NC (deep clear lake with zero interaction with sand or grass). In prepping for my trip to the coast, I noticed that my water pressure would barely move the needle at idle, and then max out in the 8 to occasionally 10 range. This seemed too low to me along with a fairly week stream, so I took it in to have it checked out. I did mention the popit valve, clean out filters, etc, and the mechanic said something to the nature of "sure, we're aware of all of that and will check it out". So, they did a complete lower unit rebuild (their words, not mine) and assured me it was dialed in. I got it back, and what I'm finding now is that at idle, I'll get 7-8 which is much better than the 1-2 I was getting before. However, as I throttle up, pressure increases all the way to 11-13 up to around 2800 rpms, and then it drops back to 9 or so and will mostly stay there up to full throttle. When I throttle back down, it stays at that 9 or so range until I get to 2500-1800 rpm's or so and it will come back up to around 12 or so, drifting back to 7/8 at idle. The motor has run fine, but it just doesn't seem right to me that the pressure drops back to 9 once I hit around 2,800 rpm's. Seems to me it should keep rising up to full throttle.
As for the telltale, water is coming out fine, but not a hard stream like I seem to remember when it was new. Also, as I get up to higher rpm's, it comes out almost in a spray rather that a tight stream. I can also confirm that the discharge hose just before the exit point while not being crimpled, it is definitely flattened out a bit as it makes a bend. Maybe that has something to do with the spray? I know I've had water hoses before that flatten out a bit without crimping, and they seem to work okay. However in this case, I would think any kind of flattening could cause somewhat of a restriction.
Any thoughts or recommendations are greatly appreciated.
Thank you,
TW
Bought Mako 18LTS with 115 Optimax 2 cycle back in late 2014. The motor had generally run pretty well. I do take it down to the NC coast and get in some fairly shallow water that has some grass and I'm sure I have skimmed the bottom a few times. Last September (2020), I was running at high rpm's and got some tones and the engine dropped down to idle or somewhere in that range. I took it in and was told the problem was the water pump as it had never been replaced. They acted as if it was common to need to replace the water pump every 2-3 years if running inshore down at the coast. So, the water pump/impeller was replaced, I fished some more last fall through this July in Lake Norman in NC (deep clear lake with zero interaction with sand or grass). In prepping for my trip to the coast, I noticed that my water pressure would barely move the needle at idle, and then max out in the 8 to occasionally 10 range. This seemed too low to me along with a fairly week stream, so I took it in to have it checked out. I did mention the popit valve, clean out filters, etc, and the mechanic said something to the nature of "sure, we're aware of all of that and will check it out". So, they did a complete lower unit rebuild (their words, not mine) and assured me it was dialed in. I got it back, and what I'm finding now is that at idle, I'll get 7-8 which is much better than the 1-2 I was getting before. However, as I throttle up, pressure increases all the way to 11-13 up to around 2800 rpms, and then it drops back to 9 or so and will mostly stay there up to full throttle. When I throttle back down, it stays at that 9 or so range until I get to 2500-1800 rpm's or so and it will come back up to around 12 or so, drifting back to 7/8 at idle. The motor has run fine, but it just doesn't seem right to me that the pressure drops back to 9 once I hit around 2,800 rpm's. Seems to me it should keep rising up to full throttle.
As for the telltale, water is coming out fine, but not a hard stream like I seem to remember when it was new. Also, as I get up to higher rpm's, it comes out almost in a spray rather that a tight stream. I can also confirm that the discharge hose just before the exit point while not being crimpled, it is definitely flattened out a bit as it makes a bend. Maybe that has something to do with the spray? I know I've had water hoses before that flatten out a bit without crimping, and they seem to work okay. However in this case, I would think any kind of flattening could cause somewhat of a restriction.
Any thoughts or recommendations are greatly appreciated.
Thank you,
TW
