NEED HELP first outboard

[jesse94954]

Hey everyone one my name is Jesse. I'm new to the forum and new to outboard motor. I recently picked up a mercury thunderbolt 7.5 hp the serial number is 5938035. After buying the motor i found out it wasn't pumping any water up to the motor and i ended up over heating the motor. I ended up replacing the water pump in the lower unit after replacing the water pump i had water coming out of the pee hole but it is coming out extremely hot i was told to flush out the line and change the thermostat.

My question is what is the best way to flush the lines and where is the thermostat located at i have looked all over with no success in finding the thermostat any help would e great trying to get the fig out before the Saturday so i can go fishing. Thank you in advance

 

[60sboater]

Your's is a '82 and I don't know where the stat is. I have a '76 7.5 and it's on the left side-top when viewed from the rear of the engine. The hose for the tell tale exits from it and goes to the fitting on the lower right(rear view). Maybe yours is there too.

How do you know it's too hot? My '73 9.8 tell tale water is fairly warm but not hot so as to burn your finger if you touch the stream.

 

[Chinewalker]

If it has a thermostat - and it was apparently an option on those motors - it would be as 60sboater described, port side, top of the exhaust cover. I recently went through a 1984, and it did not have it.

Less important than the temp of the water, how's the temp of the motor? If you can hold your hand on it, you're likely fine...

 

[MTboatguy]

My 9.8 gets warm to the touch and the stream coming out of the pee hole is pretty warm, but is not hot enough to burn, if you can put your hand under the stream and it does not burn, you should be fine.

 

[jesse94954]

Hello Guys. Thanks for the advice it is a great help.

60sboater I looked where you mentioned as well as I found a manual with the schematics of the engine but it looks as though I don't have a thermostat on this engine. I currently have it sitting in a 55 gallon drum and when i put my hand under the pee hole I can only hold it there for a few seconds. I had my wife test it as she is better at telling that stuff and her thought was the same it is hot but she doesn't feel that it is burn/scold worthy in regards to being hot unless you keep your hand there for a longer period. But something that I did notice is that the water is sputtering and is never a constant stream.

Chinewalker I did as you mentioned and put my hand on the motor. The motor is not running hot at all, it is a smidgen warm as expected I can keep my hand on it for a good 30-40 seconds before it starts to get warm.

 

[Chinewalker]

If you can hold your hand on it, it's likely cooling sufficiently.

 

[Guest]

i have a newer 2006 merc 15hp and it pisses like a race horse with warm water but you cannot keep your hand on the block longer then 3 seconds before it burns you

 

[jesse94954]

Thank you everyone i will be taking the boat out on saturday for couple of hours just to test the motor out before i take it out in open water. I will let you know how everythings goes. Once again thank you all.

 

[60sboater]

My '73 9.8 (new impeller) will not give a good stream at lower engine speeds...sputters and blows steam. I have used it twice (keeping RPMs high enough for a good flow) but I need to find out what is restricting flow. There's a washer right under the power head that can warp and interfere and deposits in the exhaust areas of the PH can have sediment build-up. Using it like this is probably not a wise thing but I was eager to get it out for awhile.

Research poor flow if you need more advice. Good luck and tell us what you find and any other adventures.

 

[jesse94954]

Hey everyone

So a little update on the outboard. I took it out yesterday. The water pump was pissing like a race house. So the engine was dependently staying cool. But had a other problem The whole hour we were on the water i wasn't able to get more the 6 mph and toward the it started to die out and all the sudden it started to run great i was able to hit 10 or 11 mph. After getting home i checked all the wires and notice the top spark wire wasn't good. i ohm them out with a multi meter and was getting a good reading.I think i was ruining on cylinder until toward the end Could a wire be a cause of the that?

 

[60sboater]

Yes it could.