86 Merc 45 classic 50 cooling

I have a 86 Tracker with a 86 Mercury 45hp classic 50, 4cyl.

Im getting it ready for this season of fishing. It belonged to my dad and he passed away 4 years ago, i have had it on the water several times and it runs like a charm, no complaints. I keep the boat at a lake house in East Texas but i brought it home last summer and it has set in my driveway all covered up for the last 5 months or so.

I did notice on my last outing in the boat that there was no water coming from the P tube.
Well this morning i dropped the lower unit and replaced the Impeller, I also pulled the tube off that comes out of the head and leads down to the exit area for the P tube. I used a coat hanger and cleaned it out and blew some air through it, evidently a DirtDobber decided to make a home in it. It was completely stopped up.

Well i put the lower unit back on the motor tightened everything back up etc... and decided i would crank it up. I wanted to use a big tub of water to set the lower unit in instead of a hose assembly, because i did not want to have water being forced into the motor. I wanted to make sure it was pulling the water in.
I started it up and NO water from the P tube. So i shut it down

I moved the tub and hooked the water hose assembly to the lower unit and fired it up. No water from the P tube and i did not notice any water coming out the prop area either, so i shut it down.

Sorry for the long winded story here but i wanted to cover everything.

My question is. Is there a way i can tell if water is being sent through the motor or any trouble shooting tips i can use to determine where the problem may be.

Re: 86 Merc 45 classic 50 cooling

Drop the lower unit a make sure the water tube was in right and while it's down hook a w/hose direct to the tube and ck your flow at the engine

Re: 86 Merc 45 classic 50 cooling

u could have more dirt guys in the motor
pull the t-stat to see if water is coming up there

Re: 86 Merc 45 classic 50 cooling

No thermostat on this motor. Hooking up a water supply to the copper water pickup tube with the lower unit off is a great way to assure you're getting good circulation thru the motor.

If you find water's not getting up there, you'll want to first remove the cyl block water jackett cover (the one that's over the spark plug holes, it's just a cover not a cyl head). This opens up the entire cooling chamber around the cylinder castings and it'll be very apparent if any silt buildup is in there.

This cover is held on with 1/4-20 bolts which, if stuck, will easily break so don't force them. If any don't want to come loose with normal force from hand tools, heat the bolts and surrounding area carefully with a propane or MAPP gas torch; this should loosen them right up.

If you have no joy after the cover's removed, the water tube's rubber grommet under the powerhead may be squeezed shut, which would require pulling the powerhead to replace the grommet. Hopefully it doesn't come to that.

Go to www.mercurypartsexpress.com and plug in your motor's ser # for access to parts diagrams for your motor.

HTH & G'luck.......ed

Re: 86 Merc 45 classic 50 cooling

First off, thanks for the reply's this is a great forums board and ive been reading it for a while. this is just my first poet in here.

I seen Laddies reply in here earlier tonight, so after dinner i went back out and pulled the lower unit off and put the water hose into the copper tube and everything looks great! good water flow out the P hole.

So it very well may be i did not have it lined up. but the other thing i noticed after i pulled the lower unit back off..And i feel like a heel about it.. I put the impeller in backwards.

I'll do a reply tommorrow after i put it all back together. Thanks again for the reply's. I'll probabally be doing another post later because i did notice some fuel on the butterfly of the top carb and it looks like it dripped down to the bottom carb and on the bottom of the housing area. Guess i'll tackle that job tommorrow afternoon.

I ordered a manual for it and have been using the online information (subscribers) until it arrives.

Thanks again guys, i'll post a follow up.

Re: 86 Merc 45 classic 50 cooling

If the impeller fin were still backwards after starting the engine then the key is not in the imp properly and the imp is not turning as on startup the fins are turned the right way

Re: 86 Merc 45 classic 50 cooling

After installing the NEW impeller and finally getting the shift shaft to align properly, I started it up and it ran perfect.
I had a good flow of water coming out of the Tell/Tale i removed the cowling and noticed something that definately makes me concerned.

<b>On the top sparkplug there is a small hole to the left of it, it had water coming out of it.</b> My first reaction was similar to a cars water pump when the seap hole starts to let water through it means its going out. Do i have a head gasket or something wrong here or is this a normal thing?