Engine overheating??

[vtlandlubber]

Hi There,
We have a 1990 2100 bow rider and are newbies. I started the boat in the driveway a few days before by running it with the mouse ears and my hose connected, and the motor ran fine. The ears popped off, so I shut 'er down.

Idling at the dock, I noticed the temp was running a little hot ( right of 180°). As we continued out the temp rose to 220° but was running fine. I was able to get it down a little by increasing our speed, but it kept hovering at 220.
Stupidly, I kept going as the needle wasn't increasing or pegging out. Well, she started clacking followed by a bang, at which point she quit. I was able to crank her over and it was trying to fire, but nothing.

Did I kill the motor, or is it possible the impeller snapped? The motor seems free and cranked out after it stalled. How would I trouble shoot this? I'm reluctant to try to start it as I don't want to further damage the motor.

Any ideas??

Thanks

Stupid-in-vermont

[jrsick]

First, check to ensure that you have enough engine oil. If oil level is good, then change both the impeller and thermostat. This is a good idea since the boat is new to you and should take care of the temp problem. Then run it shoreside and allow the engine to run for a few minutes at normal operating temp.
Impellers don't snap but that do become less efficient to the point that they can't get enough water to the engine driven water pump.
The clacking noise is common with low oil levels, but could also be caused by over-temp.

[pascavone]

hey, trying something new is not stupid, as a boat is "break once, fix twice....."

the mouse ears falling off probably burned up your raw water impeller, as its just a rubber thing in a plastic housing.

If the garden hose is not on fast enough, it will burn up the impeller.

boiling point is 212 so 220 will not melt the engine, as it burning fuel at 1600 degrees.

But, Your engine computer may have an error code, which puts it in safe mode, so your don't damage the engine.

The clacking, was probably the last of your raw water pump or the belt slipped off.

your boat is 23 years, old, so it will have a few pissy moments.

[mmwjr]

220 is hot for an open system should be around 160. Closed systems run around 220 but being under pressure the water boils at at much higher temp. IMHO it's 50/50, I have seen engines be Ok with no issues and I have seen them die if not immediately with-in 6 months (happened to my best friend, but he really cooked the engine).

Anyhow replace impeller, check oil for level and signs of water, and do this regularly for the rest of the summer looking for sign of it going south. May want to pick up a handheld thermal IR temp sensor and check engine temp (t-stat housing, risers, manifolds), I do this twice a year at the begining and mid season just for sanity.

[vtlandlubber]

Thanks to all who responded. I did check the oil level and it's full--no sign of water in oil. So hope springs eternal. I will have my boat guy check the impeller and raw water pump. Belt did not slip off.

Thanks for giving me hope guys.

Cheers,

[shrew]

Originally Posted by vtlandlubber

Thanks to all who responded. I did check the oil level and it's full--no sign of water in oil. So hope springs eternal. I will have my boat guy check the impeller and raw water pump. Belt did not slip off.

How did you check for water in the oil? The dipstick will not turn milky white. you're going to have to pull a valve cover or do an oil change.

Overheating badly, then clacking followed by a BANG, then dead in the water is not usually good. short of a belt, I'm guessing parts got hot and some moving parts decided to stop moving, while others continued.

If you were allowed to continue running above 800 rpm while over 200 degrees F, then your engine doesn't have a 'guardian mode'.

[mmwjr]

Yea Shrew I'm not thinking this will end good.

I know you said it cranks but does it make any strange noises when doing so. Clacking is either from lose of oil pressure or valve train coming apart. BANG! what else is there say.

Install a new impeller see if it starts and take it from there.

[ss3964spd]

It'sa 1990 - likely no computer to protect it.

220 in an open cooling system is a no go. Water boils at 212, creating steam (any signs of steam?). The temp sensor needs to be immersed in liquid to provide an accurate reading. IF the water boiled it's possible the temp sensor was not reading correctly and the engine may have been even hotter than 220. So while an engine with a pressurized cooling system can survive running hotter than 212 - and they frequently do, an engine with an open cooling system can't - at least not for long.

The clacking and then bang does sound rather ominous, as does the inability to restart the engine. You now have two symptoms, running too hot and no start. I'm afraid I don't believe resolving the former will also resolve the latter.

Regarding the running hot issue, how long was the engine running after the muff's came off? A matter of seconds or a matter of minutes?

Dan

[vtlandlubber]

220 in an open cooling system is a no go. Water boils at 212, creating steam (any signs of steam?). The temp sensor needs to be immersed in liquid to provide an accurate reading. IF the water boiled it's possible the temp sensor was not reading correctly and the engine may have been even hotter than 220. So while an engine with a pressurized cooling system can survive running hotter than 212 - and they frequently do, an engine with an open cooling system can't - at least not for long.

The clacking and then bang does sound rather ominous, as does the inability to restart the engine. You now have two symptoms, running too hot and no start. I'm afraid I don't believe resolving the former will also resolve the latter.

Regarding the running hot issue, how long was the engine running after the muff's came off? A matter of seconds or a matter of minutes?



It ran for about 30 seconds after the muffs came off.
Boat's at the shop for an estimate. My wife is more optimistic than me. Live and learn (the hard way)

Thanks folks.

[vtlandlubber]

Just got the estimate. One dead cylinder. A new 5.0L Merccruiser long block with parts and labor plus new impeller $5000.

Guess we'll bite the bullet and do it once I get re-employed.
Thanks again to all who posted.

Stupid but wiser in VT

[mmwjr]

Not surprised about the outcome. Quote is in line with what I have others paid (new or rebuilt long block?).

Best of luck finding work.

We all learn the hard way at some time in our lives.

[pascavone]

the good news is one cylinder dead mean valves.

I'd just pull the head off, if all over cylinder are equal in psi.

Could be as easy as a $16 bend push rod or head gasket.

[vtlandlubber]

Great idea, pascavone. I'll try that once I get the boat out of storage.
Can anyone recommend a decent repair shop in the Burlington, VT area??

thanks

[mmwjr]

When you stored the boat did you get all the water out of the cylinder? Also did you fog it with fogging oil. If not the piston rings may now be siezed. Pull the spark plugs and see if you can turn the engine over by hand.

[vtlandlubber]

New development.
After getting the boat out of the water and suspecting the shop I got the estimate from was not reputable, I put the muffs back on today, checked oil level, turned on the water supply, and attempted to start the motor.
It started right up, ran quiet and idled fine. I ran it up to 2000RPM with no knocks or other sounds and no smoking. I then engaged the prop and it did not turn in forward, went to reverse and it turned, then back to forward and it rotated.

Hearing some noise from the prop area so now, I'm guessing the motor survived and I must have broken the impeller and water pump. Going to take it to another service dealer and have the gear box and water pump serviced, and engine oil changed.

Silver lining. Fingers crossed.

Again mucho thanks to everyone who replied. Will keep you updated. Hope springs!! My wife has forgiven me.

BTW I did drain the motor before storage last winter. Seems to be fine now.

[mmwjr]

So what happened to the dead cylinder? The engine will run fine with a dead cylinder when not under load (in the water under way). Have the new dealer check the engine compression.