1997 175HP Oceanrunner Idle Adjustment

[carboman]

Hi,

I replaced my VRO pump with the one in the attached picture. Since then, the engine has run great, but..... seems like when the summer arrives I get vapor lock.
Starts up fine, runs great until the engine heats up after running normally for a while. Shut off the engine and sit for 15-20 minutes, fire back up. Then when i try to go above 1500 rpm, it will stall and die. I have to feather the throttle or let the engine idle a while before it will go above 1500 rpm.

Service manual says to back the idle screws out 6 turns from the seated position, which is where I had them.

I turned all 6 in one turn (5 from seated) and it was worse. I backed all 6 out 2 more turns (7 out from seated) and it was better.

Just wondering how far out I can go without screwing anything up.

Thanks!

 

[dingbat]

The motor doesn’t run once it gets up to operating temperature but it runs “great”?

You substituted a homemade (inadequate), work around pump attached to a chuck of aluminum bolted to the block and don’t understand why it vapor locks?

Install a proper VRO pump and I bet the problem goes away.

 

[carboman]

The motor doesn’t run once it gets up to operating temperature but it runs “great”?

You substituted a homemade (inadequate), work around pump attached to a chuck of aluminum bolted to the block and don’t understand why it vapor locks?

Install a proper VRO pump and I bet the problem goes away.

Harsh, eh? You did not answer the main question and i'm happy you didn't.

Thanks for the effort Dingbat.

 

[Chris1956]

Unfortunately those 60*V6 motors from that era tend to do that. It has been called heat soak.

I do not know the fix, but the workaround is to let 'em fast idle after restart for several minutes until the heat soak is gone.

They do that with the proper OMS (VRO2) pump installed.

I would make sure that your new fuel pump is adequate. If she will run at full throttle for a few minutes, without loosing RPM, it is probably working OK.

 

[carboman]

Unfortunately those 60*V6 motors from that era tend to do that. It has been called heat soak.

I do not know the fix, but the workaround is to let 'em fast idle after restart for several minutes until the heat soak is gone.

They do that with the proper OMS (VRO2) pump installed.

I would make sure that your new fuel pump is adequate. If she will run at full throttle for a few minutes, without loosing RPM, it is probably working OK.

This is great info, and I thank you for this! The new fuel pump works great all through the rpm range. I put new plugs in and am going to test it tomorrow. Im also going to back the idle adjustment screw out if needed.
I will reply with the results.
Thanks again .