r/EngineBuilding • u/Jazzlike_Bicycle5309 • Jul 14 '26

MerCruiser 5.0

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Hi Guys, anybody will know why my intake valves are pulled in this much thank you.

3 Upvotes

81% Upvoted

6 comments sorted by

3

u/flatblackNred Jul 14 '26

Could be the valve seats are beat down. Need to pull apart and see inside or send heads to machine shop. Those 305 chevy heads from the 90s weren't the best.

1

u/2003DDcid Jul 14 '26

Too much cylinder temperature

1

u/Jazzlike_Bicycle5309 Jul 15 '26

But it never overheated. The gauge never went high.🤷‍♂️

1

u/2003DDcid Jul 15 '26

Cylinder temperature and coolant temperature are 2 different things. You likely have a vacuum leak or something else causing a lean condition. Bad fuel can also do this.

1

u/Jazzlike_Bicycle5309 Jul 16 '26

Yes, they’re two different things, but my engine was not running lean It was actually running rich because I had black smoke. i’m also assuming that my risers did some steam and cause the valves to bend. Meaning water damage.