Troubleshooting and Diagnostics 2001 4.3

[skipper123]

Engine 2001 4.3 Mercruiser- location 2001 18ft Starcraft-symtons 5qts water in crankcase-quizing pre owner, temp guage never ran hot, boat ran for weeks after spring startup with no issues. Out on the lake having a great time and engine shut off at idle speed. Pulled dip stick looked like choc mike shake. OK this is where I fit in. Just bought this baby and drained 5qts of H2O for the crankcase WOW that was a lot of water. Poured 2 qts of oil back in it and let it run out in the oil drain pan as well just to push some more water out of the oil pan. Replaced the oil filter. Spun the engine with socket not locked up WOW again. Yes I know this is stupid but I plan to pull the plugs today, run a compressin test, squrit a little oil in each cyl fill the crankcase with oil spin the engine if it will and start it up with the outdrive in a tub of water. I would really like to know how the water got in the crankcase before I drop in a new engine and that external part with the crack that I missed blows my new engine. I read the section on water in the oil but thats info not troubleshooting. Besides the compression test and a cly pressure test with a air hose where should I be looking for leaks. I have a puddle of oil on top of the intake manifold but not sure where or how it got their. Does the intake have water jackets in it ? I dont mind spending a little extra money for the tools or supplies to do a full diagnostics on this engine.

 

[Bt Doctur]

My guess either a manifold had cracked or the bottom of the intake manifold rotted away under the thermostat

 

[alldodge]

Engine 2001 4.3 Mercruiser- location 2001 18ft Starcraft-symtons 5qts water in crankcase-quizing pre owner, temp guage never ran hot, boat ran for weeks after spring startup with no issues. Out on the lake having a great time and engine shut off at idle speed. Pulled dip stick looked like choc mike shake. OK this is where I fit in. Just bought this baby and drained 5qts of H2O for the crankcase WOW that was a lot of water. Poured 2 qts of oil back in it and let it run out in the oil drain pan as well just to push some more water out of the oil pan. Replaced the oil filter. Spun the engine with socket not locked up WOW again. Yes I know this is stupid but I plan to pull the plugs today, run a compressin test, squrit a little oil in each cyl fill the crankcase with oil spin the engine if it will and start it up with the outdrive in a tub of water. I would really like to know how the water got in the crankcase before I drop in a new engine and that external part with the crack that I missed blows my new engine. I read the section on water in the oil but thats info not troubleshooting. Besides the compression test and a cly pressure test with a air hose where should I be looking for leaks. I have a puddle of oil on top of the intake manifold but not sure where or how it got their. Does the intake have water jackets in it ? I dont mind spending a little extra money for the tools or supplies to do a full diagnostics on this engine.

There is a water jacket in the intake, your thermostat housing is bolted to it. Oil on top the engine is probably coming from the valve cover vents. My guess is the engine block is cracked, or it overheated and blew the head gasket. If it cracked it probably was caused like so many others did this winter from improper winterization. If the statement of ran for week this season came from the PO, then this is suspect. It could have come from over heat and the head gasket could be damaged.

Pull plugs and do compression and leak down test

 

[skipper123]

Well compression test showes #4 cly at 80 with the rest at 140 plus. #4 has a slow leak down but shes shot either way so Im pulling the engine loose now. Was fixing to pull the intake but the distributor dont look like it has enough room to pull out in the boat so I will pull the intake after I get it out of the boat. Pulled the exhaust manifolds and they look new and not one broke off bolt. Heck the bolts even look new and took them out with a small 3/8 ratchet. That was a first for me. My main concern now is to find the culprit so as no to reinstall it on the new engine. The only thing I found wrong is the y pipe flapper was broke off on the starbord side which was the same side as the #4 cly. HUMMMM

 

[skipper123]

Well after pulling engine and intake found the problem. Block cracked in the valley just below heads on both sides 6 inches on right side and 4 inch crack on left side. Time for a new engine or rebuild. Checking prices now. Kinda funny looking the engine after a quick pressure wash looks brand new. Exhaust bolts even look brand new. Must be a very low hour engine.

 

[jester31]

That's the way they freeze up in the winter, ask me how I know?,,,Been there, Done that many years ago

 

[achris]

....quizing pre owner, temp guage never ran hot, boat ran for weeks after spring startup with no issues. ....

I'd say that statement is looking very dodgy right now.... ie, he's full of it!

 

[zealer]

Ha, sounds like our boats are clones of each other! I also have an 01 Starcraft 1810. Improper winterization from previous owner caused similar issues. Cracked block and intake manifold. It is real fun working on this motor back there... I used a truck motor to replace mine. I have a thread here in this section. I just need to time and adjust idle, then I'll be testing her later this week.