John E3
Active Member
I finally got to firing up the engines for pre-launch check out and was greeted by a hydrolocked cylinder. Apparently the exhaust manifold failed internally and filled a cylinder full to the top. Thankfully it only turned a slight fraction, so I don't think any (more) damage was done.
I was hoping to put off exhaust & riser replacements till next winter due to the extensive amount of other maintenance that was needed. I think 2 owners ago let maint slip, and last owner just used it for a season (no maint AT ALL), and sold it to go back to sailing. So, the time is upon me, now.
Unfortunately it looks like I'm probably not going to get the old manifolds off without drilling bolts. 1 is already missing, 2 snapped, 3 are rusted away and 2 don't have clearance for an impact socket, and probably rusted too much already. This is the "easy" side, too. The outboard side can only be seen with a mirror. The other engine exposed side looks similarly bad. I'm also concerned that the whole engine is well worn. They read 1250 hours, and the heads were done some time ago. They are 7.4 Horizon MPI, 385HP, which is the Gen 6 HO version. With 4 plugs out I can still easily turn the crank with almost sign of compression on the other cylinders. Of course it takes probably a full minute to rotate it 2 turns, but I would expect some resistance. The compression gauge goes over with me on the next visit.
Assuming that I don't find a good result, the next challenge is how to get them out. I searched around here and didn't find an similar arrangements on pulling engines. In the Aft Cabin models (and probably the MY's too) the engines are under the floor of the salon, with pretty decent sized hatches. There appears to be an access panel in the salon ceiling, and a hatch on the helm floor. Might it be as simple as cutting the caulk around the hatch perimeter and lifting it out?
The effort to do this and just pluck them out is probably nothing compared to rusted/snapped bolt fight in the bilge. The marina yard has a setup on their travel lift just for this purpose. I have the tools and experience to drill out bolts, but low confidence I can drill them accurately enough in place, and may not even be possible on the outsides. If they come out, long blocks are going back in otherwise we will be sitting out the season. Paying someone to rebuild them probably doesn't make sense.
I was hoping to put off exhaust & riser replacements till next winter due to the extensive amount of other maintenance that was needed. I think 2 owners ago let maint slip, and last owner just used it for a season (no maint AT ALL), and sold it to go back to sailing. So, the time is upon me, now.
Unfortunately it looks like I'm probably not going to get the old manifolds off without drilling bolts. 1 is already missing, 2 snapped, 3 are rusted away and 2 don't have clearance for an impact socket, and probably rusted too much already. This is the "easy" side, too. The outboard side can only be seen with a mirror. The other engine exposed side looks similarly bad. I'm also concerned that the whole engine is well worn. They read 1250 hours, and the heads were done some time ago. They are 7.4 Horizon MPI, 385HP, which is the Gen 6 HO version. With 4 plugs out I can still easily turn the crank with almost sign of compression on the other cylinders. Of course it takes probably a full minute to rotate it 2 turns, but I would expect some resistance. The compression gauge goes over with me on the next visit.
Assuming that I don't find a good result, the next challenge is how to get them out. I searched around here and didn't find an similar arrangements on pulling engines. In the Aft Cabin models (and probably the MY's too) the engines are under the floor of the salon, with pretty decent sized hatches. There appears to be an access panel in the salon ceiling, and a hatch on the helm floor. Might it be as simple as cutting the caulk around the hatch perimeter and lifting it out?
The effort to do this and just pluck them out is probably nothing compared to rusted/snapped bolt fight in the bilge. The marina yard has a setup on their travel lift just for this purpose. I have the tools and experience to drill out bolts, but low confidence I can drill them accurately enough in place, and may not even be possible on the outsides. If they come out, long blocks are going back in otherwise we will be sitting out the season. Paying someone to rebuild them probably doesn't make sense.