scoflaw
Well-Known Member
- Aug 10, 2011
- 6,395
- Boat Info
- 1999 Powerquest legend 260 sx 502 mag
2005 Baja 242 islander 496
- Engines
- 502 mpi Bravo 1
496 mag B1
Don't look good. I would punt.
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
I agree. This engine is done. Save your money for a replacement.Don't look good. I would punt.
Thank you for all of the advice! It is much appreciated. I think I will just replace the head gasket and put it back together. Hopefully it will run well enough (and not overheat), to get a few more runs in before it gets pulled out for the winter. I guess it’s time to go motor shopping.I agree. This engine is done. Save your money for a replacement.
Ha, it’s a good thing I have two of them!Make certain you have your towing coverage payed up.
FWIW, that cylinder does have good compression. The mechanic at the marina said he thinks it is corrosion from coolant sitting in the cylinder over the winter.The pitting did not look good.
Well, I got it all back together and took it for a long cruise. The overheat issue is fixed, and I can now confirm the head gasket was the cause. It ran great at cruise RPM, good oil pressure and temps. However, it still sounds like marbles in the transmission at idle. Others have related that to a miss-fire, and cylinder 6 still only has about 70 psi., all others over 100. That being said, I decided to order a new long block from Michigan Motorz.I agree. This engine is done. Save your money for a replacement.
Might be the impeller on the Starboard motor.Well, I got it all back together and took it for a long cruise. The overheat issue is fixed, and I can now confirm the head gasket was the cause. It ran great at cruise RPM, good oil pressure and temps. However, it still sounds like marbles in the transmission at idle. Others have related that to a miss-fire, and cylinder 6 still only has about 70 psi., all others over 100. That being said, I decided to order a new long block from Michigan Motorz.
In retrospect, I am still glad I replaced the head gasket as I had never done one before. It was a great learning experience for me, and I learned a ton about my boat! Thank you to all who offered advice along the way.
All was going well on my ride until the starboard motor (the good one) overheated on my way back to the marina. Unbelievable luck! The coolant escaped from the cap! I did a quick compression test and all looks good, so I replaced the coolant and ran it for a while and could not duplicate the issue.
The boat is now out of the water and shrink wrapped until spring. I guess I will start the season with one new motor and another ghost to chase!
Water flow was normal. What would cause the cap to release the pressure? Or better put, cause the pressure to exceed 16PSI (assuming the cap held to that value). A head gasket would certainly pressurize the coolant side, but I would see that leak on the compression test. Maybe the cap is defective? Or maybe air is being introduced somewhere causing the coolant to boil over. Lots of possibilities.Might be the impeller on the Starboard motor.
Assuming this has not happened before......I would not jump to a head gasket.....although I can understand your focus on that.Water flow was normal. What would cause the cap to release the pressure? Or better put, cause the pressure to exceed 16PSI (assuming the cap held to that value). A head gasket would certainly pressurize the coolant side, but I would see that leak on the compression test. Maybe the cap is defective? Or maybe air is being introduced somewhere causing the coolant to boil over. Lots of possibilities.