Ohthatguy Report post Posted April 3, 2022 Does anyone know what PSI is generated in the engine by the impeller? And maybe more importantly, how much is too much before risking hurting something? Contemplating adding an electric pump to the mix to operate at low rpms. I just don't trust the flow from the impeller when putting around. I replace it every year but thinking adding an auxiliary pump would give me some piece of mind. Anyone ever added one? Share this post Link to post Share on other sites
Roosevelt Mark Report post Posted April 4, 2022 Do you have a psi Guage on your dash? If not get one. They do not like to troll or idle for very long. Its good you replace it every year I have mine done every other year. You can buy the cups that you screw in on your intake and they help a bunch. Looking at the motor peeing is not enough, its all about the PSI. Especially on a Mercury. I have a merc 07 150 efi on one of my boats and I am 7 psi at idle or in gear at idle. In the teens when ripping. 1 Share this post Link to post Share on other sites
Ohthatguy Report post Posted April 4, 2022 57 minutes ago, Roosevelt Mark said: Do you have a psi Guage on your dash? If not get one. They do not like to troll or idle for very long. Its good you replace it every year I have mine done every other year. I had to go look but yes, it does have a gauge. Either lack of IQ points or confidence, but I don't know why but I don't recall watching it. I disconnected it at the coupling in the back of the boat, not at the engine, and the gauge appears to work and I get air through the engine when checking the other way. You can buy the cups that you screw in on your intake and they help a bunch. I'll look into those. Looking at the motor peeing is not enough, its all about the PSI. Especially on a Mercury. AGREED!!!! Last trip out it didn't want to pee at all at lower RMPs but seemed to pee fine on plane. However, I couldn't go for more than a minute or two before the over heat alarm sounded. I wish I had been watching the PSI when it was peeing and over heating/beeping at the same time. (Had me scared it was something other than a bad impeller but it ran just fine after replacing it) I have a merc 07 150 efi on one of my boats and I am 7 psi at idle or in gear at idle. In the teens when ripping. Danka Thank you for the info. Share this post Link to post Share on other sites
Green Bullet Report post Posted April 4, 2022 Just replace the impeller on an annual basis and you will be fine 99.9% of the time. If adding something extra was economical or beneficial everyone would be doing it but FYI nobody is. Share this post Link to post Share on other sites
tontotom Report post Posted April 5, 2022 Get a temperature gauge Share this post Link to post Share on other sites
Roosevelt Mark Report post Posted April 5, 2022 22 hours ago, Green Bullet said: Just replace the impeller on an annual basis and you will be fine 99.9% of the time. If adding something extra was economical or beneficial everyone would be doing it but FYI nobody is. That's some great advice. Thanks for the knowledge 1 Share this post Link to post Share on other sites
