Trouble Shooting Engine

[lilkountree]

I'm going to repost this thread from the "Novice Boaters Forum" to here in an attempt to get more feedback and help.

Situation: I was at full throttle with a Triton Tr20 Mercury 200EFI (new rebuilt w/ 11 hours) over 54' water in mostly calm waters. I was cruising about 63-65mph with around 6,100-6,200rpm I'd say and the engine just sounded like it slipped into neutral for just a second. Well that second was long enough to (what I think) over rev the engine and sling it apart. Fellow anglers, the engine does not sound healthy at all!!! After a couple attempts at restart I said I'm just going to left this alone before the engine fall off the boat for real.

After speaking to multiple dealership and talking to various mechanics these are some of the things I've done to see what's wrong with my motor.

1) Spun hub - I've put the boat in forward gear and tried to spin the prop by hand/feet and was unsuccessful. Test failed. I did not spin the hub according to "X" mechanic.

2) Blown Gear box - I drained the BRAND NEW lower unit oil into a tub and did not see any pieces of metal where I may have sheared the gears. I did however have some very fine, dust-like metal shavings on the end of the magnet style screw. I don't know that those fine particles mean anything, so I don't want to rule this test a fail.

3) Blown engine - I pulled all the spark plugs out and none of them showed any signs of damage or excessive wear. All of those were brand new also since the motor was just rebuilt 11 hours ago. I'm also going to take the boat down to a local dealer and have them do a compression check on all the cylinder heads as soon as I get time away from this Army base.

If anyone has any more tests I can do to trial and error what my problem is, feel free to contact me via this thread or call me anytime at 931-980-7728.

Thank you

[RiverRatMD]

You said the engine didn't sound healthy. What did it sound Like? Will the prop spin when in neutral? and you should post your engine serial # also-- very helpful.

[EuropeanAM]

Compression test would be the next logical step.

[blackxpress]

Compression test would be the next logical step.

Yep. Hate to tell you this but your description sounds just like what mine sounded like when it blew the power head. It revved way up for just a second or two and then it slung apart. A compression test will tell you right away if a piston let go.

[Nova Kaw 650]

Don't these engines have a rev limiter??

[EuropeanAM]

Don't these engines have a rev limiter??

That would depend on "which" 200 EFI he has (inadequate information given to determine).