Optimax 150 cutting out at high RPM.

[Propofloor]

My Optimax 150 is having some issues I was hoping you guys might be able to help me out with before I take it in to a dealer. I have an Optimax 150 that seems to idle fine, when I am just in gear it seems to be just barely rough. I notice it, but other people on my boat don't really notice that much. I usually cruise around 3,000 RPM (28 knots) and it runs just fine. However when I get above 4,200 RPMs it will be fine then all of a sudden cut out. It doesn't die but it is enough to throw you forward a little bit, almost feels like hitting a little sandbar or something. Then it will pick up again and keep doing that if I don't back off. About a month ago I was out and my engine was getting warmer than normal, so I came home and switched out the impeller and thermostats. Now it is cooling just fine. At idle I am around 150 degrees , on plane it drops to about 104-106. But, my PSI at idle says 0.8 and at 3000 RPMs says only 1.4. Good telltale, and Smartcraft Gauges don't have any warnings, or anything during any of this. Do you think these things are related, or is there anything you guys recommend I check out first? I have changed the spark plugs, and just picked up a new water separator to install as well. The cutting out thing seems like a fuel issue to me, while the PSI thing, I am sort of at a loss for since it seems to still be cooling well.

 

[Propofloor]

Optima 150 cutting out at high RPM

My Optimax 150 is having some issues I was hoping you guys might be able to help me out with before I take it in to a dealer. I have an Optimax 150 that seems to idle fine, when I am just in gear it seems to be just barely rough. I notice it, but other people on my boat don't really notice that much. I usually cruise around 3,000 RPM (28 knots) and it runs just fine. However when I get above 4,200 RPMs it will be fine then all of a sudden cut out. It doesn't die but it is enough to throw you forward a little bit, almost feels like hitting a little sandbar or something. Then it will pick up again and keep doing that if I don't back off. About a month ago I was out and my engine was getting warmer than normal, so I came home and switched out the impeller and thermostats. Now it is cooling just fine. At idle I am around 150 degrees , on plane it drops to about 104-106. But, my PSI at idle says 0.8 and at 3000 RPMs says only 1.4. Good telltale, and Smartcraft Gauges don't have any warnings, or anything during any of this. Do you think these things are related, or is there anything you guys recommend I check out first? I have changed the spark plugs, and just picked up a new water separator to install as well. The cutting out thing seems like a fuel issue to me, while the PSI thing, I am sort of at a loss for since it seems to still be cooling well.

 

[Faztbullet]

Sound like injector(air/fuel) or spark is acting up on a cylinder...

 

[Marine Services of Las Vegas]

Year serial #?

 

[Propofloor]

1B507496.
Changed the water separator and fuel filter and now it idles and runs just fine up to about 4,000 RPM. Still cutting out very frequently. Feels just like I am hitting a rev limiter or something but I am sure that’s not it. No alarms on the smart craft gauge either.

 

[Marine Services of Las Vegas]

. However when I get above 4,200 RPMs it will be fine then all of a sudden cut out. .

"Hey Peter...whats happening, we need to talk about your TPS reports..." Maybe. The TPS is not adjustable, but the dealer does have the CDS software, but that water pressure does concern me...I'm going to PM you a few things. On #12 of the aft view not the TPS Failure on the "Guardian Protection" document the water psi sender "quick disconnect" hose and blow back through the hose (opposite way of the sender). These are small passages and problems can get clogged easily especially in hard water.

 

[GA_Boater]

Hey Marine Services of Las Vegas - PMs kill the effectiveness of the forum. Other users may be looking for advice and by going private they are disadvantaged. Please post advice in the open forum. Thanks.

 

[Marine Services of Las Vegas]

Mod EDIT: Content removed

 

[Propofloor]

I believe I have found the solution to my problem. There was a section of the fuel line that was corroded and the inner liner was collapsed and severely restricting fuel flow. It was difficult to see without taking the fuel line off and holding it up to the light to look through it as it was not on the ends of the line. I took the boat out for about an hour today and ran it WOT for a while with no problems at all with myself on board. Thank you all for your help.