Topic: Not sure as to where to post this..........

['78 LadyBird]

Anyone familuar with a 3.7 Merc inboard/outboard motor?

[hada76]

think its a 4cyl chev

['78 LadyBird]

Yes, it is a 4 cycl.  I need to know as to how much damage and or what is wrong with our boat.

Frank took the boat out, ran great, and all of a sudden the temp gauge went all the way up, white smoke from the carb, and then a clanking sound.  

The temp then dropped back to normal and Frank was able to idle to a dock.

No coolant was in the motor after all this happened.

Two things we think went wrong:

Impeller
Water pump

Dose anyone know as to how we can tell what is actually wrong?  We do not want to start it again, in fear that we may do more damage.

[bobspacin80ta]

Id say impeller. Whens the last time it was changed?

[hada76]

doesnt take much to clog the water intakes on those outdrives. weeds or a plastic bag, may have just got hot hopefully no real damage...yes check impeller

['78 LadyBird]

Oppps, the impeller was never changed out while we have owned it.
Gosh, I hope that is all and no other major damage.

With Frank being out of work............still....................we decided not to open our pool because it is too expensive to run.  So, I figured well, we have the boat to use all summer.............now this!

[Prettybird81]

doesnt take much to clog the water intakes on those outdrives. weeds or a plastic bag, may have just got hot hopefully no real damage...yes check impeller

Agreed... we have had this problem a few times when the lake was really low... we hit bottom in unexpected places just trying to get out of the dock or entering the channel. It sucked up mud, debris & weeds... then once it cleared out everything went back to normal.  I hope that's all it is so you can be out enjoying the water stress free

['78 LadyBird]

Thanks Prettybird!  
Being out on the boat does relieve my stress levels.  I just don't know if we should put the rabbit ears on and try to start it in the driveway.

[pointman]

Change the impellar now! Most I/O manuals tell you to change it at 2 year intervals - minumum! The only other thing to check is a cracked block, which is caused by improper winterizing (Not letting the engine heat up and opening the T-stat to allow anti-freeze to flow completly through the block) Trust me on these 2 items, learned the hard way!

[Rarebird]

yes the impeller is a critical part on these type of outboard drives. If this was your first excursion on the water this year you may have has a spider web/nest, (some sort of debri that temporarily clogged your cooling system and then it dislodged). I would get a "rabbit ear" or "wish bone" water hose setup to run it in your driveway to test. Since your boat is more than likely a fresh water set up I would opt to change out the impeller in the lower unit... Its not that hard to do really just the unit is alittle odd to work with but with two people its easier. Call it an insurance policy... nothing worse than having to be towed/ paddle back to dock on a summer day.

 

['78 LadyBird]

Ok, great!  I, I mean Frank and I will try doing the impeller this weekend.  Hmmmm, now where to get one.  

I guess at the marine store.  lol

Oh, by the way, there is no evidence of water or anti freeze in the oil.  This is a good sign, right?

[pointman]

That's a really good sign!