removing thermostat 68' merc 50hp

[blwood11]

67/68 thunderbolt ign. #2119719<br />I am having trouble with my pee pee! <br />Impeller is new and working fine. However when I force water through water pick up tube in lower unit, it will soon return out of the bottom but does not pee. I had found that prev owner had pinched the rubber between the head and the lower cowel but after removing, still no water. I wanted to see if the thermostat housing was clogged. nothing will happen either trying to flush from the pee end. I tried letting the engine warm enough to open thrmostat and still nothing. I did notice that the water coming out of the prop was definitly warm though. <br />I want to take out the thermostat but seems like lower cowel is in the way. do i need to remove it? is it difficult or does it simply drop down?<br />Thanks as usual!

 

[Laddies]

Re: removing thermostat 68' merc 50hp

There is no thermostat, you probable have a plugged telltale in some cases they have to be rehooked at the top of the engine block to get them to work

 

[tmcalavy]

Re: removing thermostat 68' merc 50hp

Like Laddies said...no thermostat. The previous owner may have serviced the lower unit and not gotten the water tube back in place correctly, or critters got down in the tube through the telltale hole and built a nest, or two, or bits of the old impeller are blocking the line, or sand/slug/crap is causing a blockage. You can pull the hose where it connects to the cowling for discharge and put some air down it, or a thin rod, or flush it with water. If that doesn't do it, pull the lower unit and try the same from that end. If it ain't peeing something is blocked somewhere. I had a 73 Merc 500 and it would only dribble out the telltale at idle...on the lake or at home on muffs in the driveway. Wouldn't put out a stream until you pushed the rpms up over 1000...got stronger as rpms increased. You can check for water circulation around the cylinders by touching (lightly) the side of the motor just in front of the plugs when its running. If its cool to the touch, the water pump is doing its job. If it's too warm to touch even briefly then you have a cooling system problem that must be corrected before you take it out, or you may be paddling back home. Might help to start with a Seloc or Merc manual for your year/model...I see lots of manuals on the auction and other sites for generally less than $20. If this outboard has good compression in all four jugs and the wiring is in good shape and lower unit seals are good...it is definitely a keeper. The inline four Mercs are real workhorses...just gotta get to know them and do the basic maintenance when they need it.

 

[blwood11]

Re: removing thermostat 68' merc 50hp

i've tried blowing from every end, still nothing. i think i will try laddies advice and just hook up to the top. thanks again. <br />this is a 67' and like you said, a workhorse. throttle response is like that of a dragster or something. still having trouble on the top end. lower float stuck, i have been avoiding removing to clean due to unfamiliarity. no bowl under carb?

 

[tmcalavy]

Re: removing thermostat 68' merc 50hp

The carb bowls on my 73 were part of the carb casting, but don't know about your 68...they may have been different. Hardest part of cleaning those carbs is removing all the stuff in front to get to them. Be careful of the linkage that connects the carbs on the right side...on my 73 it was made of plastic...be very gentle with the wrenches getting them off. Other than that it is a simple job really. Sounds like the float or needle valve in that carb is dirty, worn out or out of adjustment. Once you get the carbs done it should really take the bit and go on the water.

 

[blwood11]

Re: removing thermostat 68' merc 50hp

ran tell tale from top works like a charm. thanks laddies and tim