86 black max pressure gauge

[jigmister1]

can anyone help point me in the right direction for a pressure gauge?
I got a 86 175 hp black max.
where can I purchase the gauge and how dose it install?
thanks in advace!

Jim

 

[j_martin]

Re: 86 black max pressure gauge

Merc stocks em, and so do most of the gauge outfits.

There's a pipe plug on top of the block just aft the flywheel. Remove it and install a barb fitting (1/8 in, I think) for the plastic line to the pressure gauge.

Do not T into the tell-tale. That's not a pressure line.

hope it helps
John

 

[jigmister1]

Re: 86 black max pressure gauge

thank you very much. seems it could not be much easier than that!

one more question. what gauge pressure is normal and at what pressure is there cause for concern?

thanks
Jim

 

[j_martin]

Re: 86 black max pressure gauge

thank you very much. seems it could not be much easier than that!

one more question. what gauge pressure is normal and at what pressure is there cause for concern?

thanks
Jim

Mine runs about 5 at idle, goes up to 14 or so at about 2500, steps back a few then goes up to about 20 at WOT

If it's too high, somethings plugged. If it's too low, somethings leaking, or some chit got over the water pickup. Couldn't be much simpler than that.

John

 

[jigmister1]

Re: 86 black max pressure gauge

ok thanks for the information. I need to get one installed and keep an eye on it. my boat just has a temp gauge and some times she runs hot. Hits the alarm evey once in a while. It hit the alarm 2 or 3 times in the last year.
but the temp gauge was not reading much hotter than it normlay dose.

my boat is used 2 times a week on average. so its not hitting alram very often.
The waters I fish are shallow dirty and full of weeds. I am sure it sucks up sand weeds and mud at times. In fact the prop works like a tractor idling threw heavy vegetation at times.

I dont trust the temprature gauge much. I got a new one (quick silver) and in the insturctions it says that the aveargre reading is 3/4 the gauge! to me thats high. thats about were my old gauge was running at WOT. Probaly nothing wrong with the guage. I need to get a sender as well.

I prefer a guage with NUMBERS so I can see the actual temprature.
I can not seem to locate a pressure gauge on line right yet. I would like to stay with quick silver but I suppose VDO would work.
Just changed out the impeller and upper water houseing yesterday.
The impeller was showing wear but not totaly shot. I change that thing evey year.

where online can I order thermostats, pressure gauge and temprature sender all in one shot?
the merc site is not much help. getting parts for this thing should not be so hard.

 

[j_martin]

Re: 86 black max pressure gauge

It's possible to selectively plug up internal ports when you're running through weeds, algae, and other debris. The head with the overheat sensor could be getting hot early because of that. One lily pad, wrapped just right, can shut down the cooling in a heartbeat.

mercury fuddled up their online parts system big time. Some of the bigger dealers won't even deal with it, but just use the fiche and phone.

Supreme Marine in Minneapolis would likely have anything you need in stock at as good a price as you'd get anywhere. Give them a call, (612) 588-3456

hope it helps
John

 

[jigmister1]

Re: 86 black max pressure gauge

helps as always sir.


I attempted to test the temp sender to the gauge but failed.
what I did:
got some water and heated it to about 200 degrees and left a themometer in it.
unbolted the sender from the head and removed it from its well.
with the boats igntion keyed on I set the sender in the hot water.

the gauge did not move. So I figured that the gauge needs to be grounded.
so I grounded the gauge with a spare wire I had laying around.

the gauge went to full HOT without being in the water.

I know that removing a sender and grounding it to an engine block will make your gauge sweep to to the full position (on cars/trucks)
this can help trouble shoot the gauge or sender.

so I see how that happend.


but is there a way that I can check the actual? I want to see where that gauge is reading when the temp is actual 180.

do I need to some how ground the other end of the sender rather than the end with the wire on it?

Jim

 

[j_martin]

Re: 86 black max pressure gauge

helps as always sir.


I attempted to test the temp sender to the gauge but failed.
what I did:
got some water and heated it to about 200 degrees and left a themometer in it.
unbolted the sender from the head and removed it from its well.
with the boats igntion keyed on I set the sender in the hot water.

the gauge did not move. So I figured that the gauge needs to be grounded.
so I grounded the gauge with a spare wire I had laying around.

the gauge went to full HOT without being in the water.

I know that removing a sender and grounding it to an engine block will make your gauge sweep to to the full position (on cars/trucks)
this can help trouble shoot the gauge or sender.

so I see how that happend.


but is there a way that I can check the actual? I want to see where that gauge is reading when the temp is actual 180.

do I need to some how ground the other end of the sender rather than the end with the wire on it?

Jim

Look on the other head. You have the overheat switch in your hand. The gauge sender has two wires on it.

hope it helps
John

 

[jigmister1]

Re: 86 black max pressure gauge

I am sure I am on the right senser. either way both of them only have one wire.

If I ground the senser the gauge jumps to full hot.

 

[hkeiner]

Re: 86 black max pressure gauge

The below link conains some good information on how to install a water pressure gauge.

http://www.diy-boat.com/index.php?option=com_content&task=view&id=151&Itemid=49