1991 Volvo 570A w/DP A1. Fresh water cooled (heat exchanger)
At the end of last season, I took the boat out to fill it up with fuel and the water pump belt broke while in the chop just off Annapolis. I dropped the speed as low as I could and worked my way to safe anchorage in the Severn River and called for a tow. I probably ran for 10 - 15 minutes. The engine was starting to labor but not bad. It got cold the next week so the boat was parked for the season. The boat is new to me and this is my first IO, though I rebuilt an Chev small block in high school.
In March, I began repairs and have replaced the water circulation pump, the sea water pump, all the belts and one hose that looked iffy. I pulled out the heat exchanger and had it pressure tested and it was good. I pulled off the exhaust risers and they had light scaling in the water jackets covering maybe 30% of the water passages. These were easy to clean out so I assume I'm still okay. I've replaced the plugs and I believe they were light tan and dry. I pulled the Edelbrock marine carb and rebuilt it.
The engine now runs and hold temp at 160 degrees but won't idle and starts to slowly surge until it stalls. It runs like a champ down to about 1,200 rpm and dies out at about 1,000 rpm. The carb doesn't have any vacuum ports but I sprayed starting fluid around the base of the carp to check for a leak and didn't find anything. I also sprayed along the intake mainifold where it attaches to the head and there may have been a slight change, but it was hard to tell if it was just my imagination.
Searching the forums it sounds like a headgasket could be the problem but I don't want to get into that unless I have to. I haven't done a compression check yet but I guess that's next. I did note that the engine had gotten hot enough that it cooked the paint off the intake manifold on both sides where it touches the center of the cylinder heads (I wonder if there is a water jacket there). I haven't noticed anything in the coolant but haven't looked that closely. I also haven't checked the timing yet but nothing there has changed from last season.
Any ideas? Am I missing something? Do you think it's a blown gasket? I'm getting tired of "Dad, is the boat done yet?" and really want to get it in the water, but of course a boat that won't idle isn't drivable. Any advice would be appreciated.
One more thing, I don't know if this matters but it won't start cold without a shot of starting fluid.
Thanks,
Phil
At the end of last season, I took the boat out to fill it up with fuel and the water pump belt broke while in the chop just off Annapolis. I dropped the speed as low as I could and worked my way to safe anchorage in the Severn River and called for a tow. I probably ran for 10 - 15 minutes. The engine was starting to labor but not bad. It got cold the next week so the boat was parked for the season. The boat is new to me and this is my first IO, though I rebuilt an Chev small block in high school.
In March, I began repairs and have replaced the water circulation pump, the sea water pump, all the belts and one hose that looked iffy. I pulled out the heat exchanger and had it pressure tested and it was good. I pulled off the exhaust risers and they had light scaling in the water jackets covering maybe 30% of the water passages. These were easy to clean out so I assume I'm still okay. I've replaced the plugs and I believe they were light tan and dry. I pulled the Edelbrock marine carb and rebuilt it.
The engine now runs and hold temp at 160 degrees but won't idle and starts to slowly surge until it stalls. It runs like a champ down to about 1,200 rpm and dies out at about 1,000 rpm. The carb doesn't have any vacuum ports but I sprayed starting fluid around the base of the carp to check for a leak and didn't find anything. I also sprayed along the intake mainifold where it attaches to the head and there may have been a slight change, but it was hard to tell if it was just my imagination.
Searching the forums it sounds like a headgasket could be the problem but I don't want to get into that unless I have to. I haven't done a compression check yet but I guess that's next. I did note that the engine had gotten hot enough that it cooked the paint off the intake manifold on both sides where it touches the center of the cylinder heads (I wonder if there is a water jacket there). I haven't noticed anything in the coolant but haven't looked that closely. I also haven't checked the timing yet but nothing there has changed from last season.
Any ideas? Am I missing something? Do you think it's a blown gasket? I'm getting tired of "Dad, is the boat done yet?" and really want to get it in the water, but of course a boat that won't idle isn't drivable. Any advice would be appreciated.
One more thing, I don't know if this matters but it won't start cold without a shot of starting fluid.
Thanks,
Phil
