250 pro xs cracked heads!

[Cbhollin24]

I have a mechanic telling me that a cracked head is causing vapor lock and that is why I'm losing prime on the fuel line..... is that even possible! Help please!

[gehol]

Just trying to be helpful, a serial number is required on this site.

[Cbhollin24]

Don't have it At the moment the boat is in the shop

[gehol]

Without the serial they may or may not answer.

[lpugh]

I have a mechanic telling me that a cracked head is causing vapor lock and that is why I'm losing prime on the fuel line..... is that even possible! Help please!

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You may have cracked head, Cant think of any way in my wildest imagination that it could cause vapor lock or losing prime. I would love to hear the reasoning behind that one.
Take picture of the crack any post it

[Cbhollin24]

Thanks.... makes no sense to me either!

[greg88]

Very interesting keep us informed and why did the heads crack vapor locking the reason it is in the shop ????? was it running fair when it would run????

[Savage]

Oh brother!

[Cbhollin24]

The boat was running great ... carried it to shop to have it serviced and see why I was losing prime when idling around but not when running around

[haus9393]

I always seem to loose prime when my fuel filter gets extremely dirty. That’s always the first place I look.

[Buck456]

I'm tuned in. I've have had this same issue since I've owned my boat. Runs great, but if I idle for a long period of time I loose prime and yes I pump the primer bulb. Thought they had it fixed once, but it still does it.

[CenTx496]

I'm tuned in. I've have had this same issue since I've owned my boat. Runs great, but if I idle for a long period of time I loose prime and yes I pump the primer bulb. Thought they had it fixed once, but it still does it.

for what it's worth I had the same issue with losing prime on long idles out of no wake zones. I replaced the pulse pump diaphragms and problem is solved

[Savage]

Pulse pump.
Fuel Demand Valve.
Fuel lines sucking air due to improper clamps.

[bass.man65]

Would this be on a 07/08 model year?

[Cbhollin24]

Yes

[gatorsin09]

Pulse pump if you lose prime at idle

[Cbhollin24]

update on the motor and the cracked heads.... went and picked the boat up today, very unhappy with the service I was receiving. I was told the fuel lines had been replace, only to find out when i got the boat home they weren't. The motor still has the same problem of losing prime when idling. I'm going to rebuild the pulse pump, to check it off the list. I did however inspect the heads and they are cracked! So I will be replacing the heads myself. I would greatly appreciate any advice given on doing the job and the torque specs. I will post the serial # and pics. of the heads tomorrow and any other information need... thanks

[Bob G.]

I would get a Mercury Manual for your motor before you start any major repairs. You'll need your serial number.

[Savage]

The cracked heads have nothing to do with "losing prime". I'm betting that the technician noticed the heads, while looking into your original problem.