2001 Mercruiser 5.0 EFI stern drive shooting water on #7 and no compression #2

[arizonaT]

just bought a nice boat... so i thought. need some help here. had no chance to water test, only on hose due to time constraints...ooops! bought it, took it to the lake and oh boy do i have engine problems.

on a tight budget, bought a 2001 Reinell 200C 21ft Cuddy with a Mercruiser 5.0L EFI original engine with an alpha 1 stern drive, engine shows 210 hrs on the clock and cosmetically looka clean and rust free. here the issue:

1) took it out first time to lake, all fresh fluids, fresh plugs and fresh gas (boat was stored for years by previous owner
2) boat had no power in the water under load, RPMs maxed at 1800
3) revs out high rpm under no load (on hose or reverse, of course)
4) no visible cracks in any exterior surface of engine or drive was told stored winterized indoors and its a native pheonix, az boat we dont get hard freezes.
5) got boat home, there was water in the oil. light water such as from piston blow by...lightly milky not too much volume increase on dip stick levelm
6) drained oil, pulled plugs and oh boy, port side cylinder #7 shooting water out the spark hole
7) low compression on all but one cylinder (below 120) around 90s
8) zero compression on starboard side cylinder 2
9) previous owner had just done a impeller, so I expect it got hot. guy got seriously agressive after contacting him a week after buyinh boat to ask if it got hot or something on him befee he sold it. i was nice, he got crazy instanly via text so hiding something.
10) i am hoping it is manifold gaskets, head gaskets and hope i wont find any metal parts in the heads or cylinders.
11) there wasnt any banging, clacking, rattling or anything else at all when turning over the engine.

any thoughts, ideas, recommendations, help, or suggestions on how to approach this in november. boat wont run, cant be winterized properly. about to do emergency top end tear doen and inspection. only ever done PWC and automotive work. no stern drive experience. ex military and just had a baby so working on a seriously tight budget or i would just take it to a pro.

 

[tpenfield]

Sounds like the engine is broken. Revving the engine does not indicate anything.

I suspect a hydro-lock, based on the water coming out of the cylinders. Might be the manifold gaskets, but the low & no compression may indicate damage done to the rotating assembly.

Sad situation. I guess the PO got the best of that deal.

 

[Lou C]

Well you gotta take it apart. With water in a cyl it all depends on how much. I got lucky with mine, when it blew both HGs 3 years ago. Had water in #2 but not enough to hydrolock. I'd pull the plugs, and spin it over with the starter....see how it sounds...if it sounds normal as far as cranking...might be worth taking it apart to have the heads done....if not....as in you hear clunking noises from the lower end....then its time to find another engine....sounds like you already tested for that so I might want to do a cyl leak down test given you comp test results. If you have a lot of leakage past the piston rings, then it gets more complex. If it was all from the valves, pulling the heads on a Chevy small block is not that big of a deal, auto shop 101.....
I had good luck with a set of re-man heads from a local speed shop and Fel/Pro marine gaskets....re-did the top end 2 years ago....still running the original short block...original heads were cracked due to an overheat and cooling passages getting eroded from salt water use so the re-man heads were the way to go....

 

[Scott06]

Yeah with low to no compression you need to rebuild the long block. If you're handy strip it down to long block and find a machine shop that has an understanding of marine engines vs automotive rebuilds. And have them rebuild it

 

[Bt Doctur]

Start by puling the heads , could be anything from a bad overheat that took out the head gaskets or rusted valves from having water in the cylinders. You could make an adaptor to inject the cylinders with air and listen to where the sound comes from. From the throttle body= leaking valves. from the valve cover= leaking rings

 

[arizonaT]

all cylinders in port side have rust in them, starboard side no rust. head gasket blown between front 2 cylinders on port side. intake manifold and runs looked like a milkshake.

 

[arizonaT]

[No message]

 

[arizonaT]

this is the port side.

 

[arizonaT]

underside of port side valve cover looked milkshake also

 

[arizonaT]

so the good news, exhaust manifolds, risers, valves, heads, intake manifold, throttle body and rotating assembly on front of motor all look great. Do i test the EFI to see if it can be programmed for a 5.7 and upgrade to a full 5.7 long block, bolt on my good parts and reprogram brain or do I try to save this 5.0? afraid my rings may be shot. i had compression under 90psi all around and zero compresson on cylinder #2 on starbord side where no rust, good head and good head gasket. what would you all do?

 

[QBhoy]

I’m going to have a guess that it’s overheated previously and melted the exhaust flappers. A following sea or too quick slowing down or reversing hard brought water up into the engine. One of a few reasons it could happen.

 

[arizonaT]

interesting. i thought the same thing. it is a through prop stern drive exhaust alpha one. both of the butterfly flaps in the y pipe were entact and fully functional.

 

[QBhoy]

interesting. i thought the same thing. it is a through prop stern drive exhaust alpha one. both of the butterfly flaps in the y pipe were entact and fully functional.

Ah. Ok. If they are there and not melted. Maybe not the issue then...unless they have been replaced recently and after the problem started. Always a possibility.
maybe you’re on the right path with gaskets too. Hopefully you sort it out

 

[Scott Danforth]

I suspect the exhaust manifolds and joints were the reason you have water in the bores.

I would not re-use them. they are a consumable item

yes, you would need to reprogram for a 5.7

I would pull the motor and completely go thru it, determine what is the cause of the failure and what is needed prior to going in a direction

 

[Lou C]

I think that engine may have been apart before, those look like Fel/Pro gaskets not the ones that came with the original engine unless GM started using Fel/Pro at some point. My old gaskets were a silver colored head gasket and a dark orange colored valve cover gaskets. The Bluish head gaskets and blue valve cover gaskets look like Fel/Pro...

 

[arizonaT]

you guys were right about pretty much everything. engine has been apart before. found a 1/8in wide line of head gasket missing between a water jacket and cylinder #7. this has to be the water ingestion source.

also a 1/2in wide gap in between the front 2 cylinders on the port side.

sprayed marine rust prevention lube in all cylinders and turned crank by hand with socket wrench. rust on cylinder walls was all superficial and instantly went bye bye with a few turns. no slop in pistons. no vertical marks on cylinder walls, no scarring. going to have heads and exhaust components magnafluxed. looks like the rotating assembly in block is good. have no idea how to test compression with heads removed unless there is a special per cylinder tool that the shop has.


if all tests good, going to try to put all new gaskets and re-assemble. then do compression test, if good put her in the water and see what happens.

 

[Scott06]

If it's been apart you may want to measure the block and head surfaces for warpage due to over heat before you reassemble

 

[Scott Danforth]

If it's been apart you may want to measure the block and head surfaces for warpage due to over heat before you reassemble

that should be done every time the head comes off.

fore/aft, across, and diagonally

 

[Lou C]

I think the spec is warpage can’t exceed .003” measured with a mechanics precision straight edge and feeler gauges. I’d also measure the sealing surfaces of the intake manifold and exhaust manifolds and elbows. The exhaust manifolds can be propped up level and filled with acetone (careful flammable) to check for leaks.