Running issues

[bmire322]

I have a '03 Supra Launch 22sv that I bought with 360 hours. Now at 400 hours the boat idles great at 150 degrees. It will take off and then a sudden loss of power. The engine does not die but the temp gauge rises quickly to 180. After letting off the throttle, it idles fine. Everything is smooth and the temp quickly returns back to 150-160. Its consistent. Bogs down and then temp rises, continue idle and it cools off. Ive pulled the water lines on both sides of water pump just to check for any grass or trash and all is clear. Any help would be greatly appreciated. My dealer is several hours away so id like to try what I can before taking it in.

[Jetlink]

Have you checked the raw water impeller condition?

[jzelt]

Is there any difference if you hammer it to full throttle vs slowly work it to full smoothly?
Are the hoses possibly collapsing due to age?
I have had to replace the throttle position sensor, but that was because it was dumping too much fuel at idle and causing black smoke in the exhaust, not temperature related.
But being smooth on takeoff made a difference in the boat responding the way it should vs hammering it usually ended up with a stall.

[bmire322]

impeller is in good shape. Ive verified no pluggage or restriction in water flow. The hoses all seem to be in pretty good shape. Firm but not overly hard. Speaking to the service manager at dealership today he suggested a fuel delivery issue. I started to track down everything on the system but working an inboard is no easy task for a big guy. Also, jzelt it makes no difference whether its slow throttle or hammered. The issue has happened randomly at each different attempt.

[Meyeronfire]

Per the owners manual I believe 160-180 is normal temp. I have the same boat and mine seems to fluctuate a bit ... But never goes over 180.
Have you changed the fuel filter? Checked the strainer basket off the fuel pickup line? Possible debris stopping the fuel pressure. Sudden loss of power when hitting the throttle has to be fuel. How old is the fuel pump?




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[bmire322]

I'm sorry for the delay. I've been at work the last 18 hours. I'm unaware of the age of the pump. Could you describe where the filter and strainer are I'm not recalling seeing one yesterday

[Meyeronfire]

I'm sorry for the delay. I've been at work the last 18 hours. I'm unaware of the age of the pump. Could you describe where the filter and strainer are I'm not recalling seeing one yesterday

The strainer will be located on the fuel pickup line inside your fuel tank. Locate the fuel pump follow the hose back to the fuel tank and that will be the one you want to pull out and inspect, there is a small piece of mesh around this plastic pickup line that sometimes gets clogged from debris in the tank causing fuel restriction. You can try a new fuel filter also which is located on the starboard side if its a v drive. Then for sure check the fuel pressure, should be around 30psi I believe, that should rule out fuel delivery if thats your issue. I also like to see how the injectors are spraying while the boat is running on he fake a lake, just pop the plastic cover off then the spark arresstor and you can inspect the injectors and see if they are spraying evenly.

[Cusefan78]

Same problem I had. Changed the filter and it was good to go. But that doesn't explain your temp. Could be the thermostat not opening all the way . But you have two seperate problems one is cooling and the second is fuel. If you have a strainer for water check that, something is restricting water flow combine that with the fuel problem. Should be a few minor issues.

[bmire322]

Is it a possibility my boat doesn't have a fuel filter? I ran my hands on hose all the way from the pickup on tank to the rear of the engine block on the starboard side, where it tied into a motor driven pump. From there it goes to what seems to be another electric pump and then to the fuel rails. I did pull the pickup on tank and cleaned the strainer although it looked fairly clean. Hopefully I'm just missing something simple here.

[bmire322]

Also while I had the return gas line out I turned the key and there was a good flow of fuel pumped back towards the gas tank

[Cusefan78]

The easy way to tell if you have a blockage is pinch off the return line and rev it up to where you had problems. Of it goes away you know there is a flow issue.

[bmire322]

I pulled the gas cap off and ran the boat for an hour and half with no issues. This whole time was a venting issue

[jarodag99]

Bmire322-it's absolutely possible. I have an 04 22ssv I bought off the dealership floor...never had any work done on it other than routine maint I did myself. Had a fuel issue last year (finally fixed it this year) and while working it, realized I didn't have a fuel filter. Followed lines from engine, pump, all the way to tank. I even pulled floor up to replace my steering cable. Anyway, borrow a fuel pressure gauge from autozone and check the pressure when you lose power. My issue was the pump. Dropped from 30 psi to 15 when under a load after a while. New pump, problem solved. Good luck


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[Meyeronfire]

Your gas tank should have a few vent hoses you check those to make sure they are not clogged or restricted.