87 Sorrento 23 vapor lock.

[WinkBuilt]

Have had the boat on out Lake Erie 5 times now.

Other than our first voyage where we discovered the coil was shot and got towed back, the 5.7 Merc has run great.

Temp dead on at 170. Easily cruising at 25-30.

Have some things left to do still.

But my biggest issue is vapor lock at this point.

Love this boat and the motor is quiet when running do to it being so well covered.

Sun pad, back rest for bench seating, bench seat, carpeted storage deciders under pads.


Fires right up at launch ramp.

Run for a bit. Anywhere from 30 mins to an hour and a half straight with no issues.

(RPM will surge at times, but, I think that’s due to prop condition and inability to trim st this point)


Soon as we anchor though, she just won’t start up until it’s sat with engine cover open for 45-90 mins.

This has stricken major confidence issues into my wife....She missed out on a beautiful ride to Put in Bay last week.


I’ve seen everything from insulate gas lines to 12v fuel pumps to force the fuel out of line.

I have tried the letting engine idle for several mins after running, tried the leave a football between the sunpad and frame to vent. Ran bilge vent etc.


Any one else with this boat have the same experience?

Anyone beat vapor lock?

 

[El Capitan]

Looks like your 5.7 is carbed.
You’re doing the right things.
Are you running lean? Lean runs hotter. I always tweak my carbs fat. On my Harley, lawnmower and mercruiser.

 

[scoflaw]

The fix for old cars was a phenolic spacer under the carb and do the insulated sleeving on the lines

 

[WinkBuilt]

Looks like your 5.7 is carbed.
You’re doing the right things.
Are you running lean? Lean runs hotter. I always tweak my carbs fat. On my Harley, lawnmower and mercruiser.

Yea it is carbed. Idle seems high as our “no wake” speed has us cruising past other boats in the river.

Doesn’t seems to have any backfiring or “sneezing”. Carb was just cleaned and plugs are new. Is there any easy check to determine if it’s lean?

 

[WinkBuilt]

The fix for old cars was a phenolic spacer under the carb and do the insulated sleeving on the lines

I did see there’s a spacer I think by Edelbrock.

Is this the main line to insulate?

 

[scoflaw]

Hard to tell with pic but probably, you'll know soon enough when you unhook it to slide the sleeve on.
Make sure the spacer is plastic .not metal

If your passing boats at idle, it's way too high. 6-700 rpm is what you want. Hard on the drive also

 

[El Capitan]

Hard to resolve via threads. Tell your mechanic you want to richen your fuel mixture to reduce vapor lock due to fuel boiling.