US Marine 85 Force outboard 1988 Model 856X8A

Good afternoon from Scotland

I have recently ordered and received an impeller kit from Marine Engine . com which I have fitted today and I am frustrated that the water is still not circulating when the engine is running. I removed the bottom end and fitted a hose to the engine tube and removed the thermostat cover and water flowed unimpeded through this route. I sat the lower end in a tank of water and manually turned the shaft which resulted in water flowing up through the plastic outflow from the impeller proving that the new impeller was working yet when all is bolted together there is nothing coming up through the thermostat housing which is baffling.

I noticed that the thermostat was missing from the housing indicating that a previous owner had been having problems presumably with overheating.

Can anyone advise how best to proceed or what to check next please.

Best regards
Bill Paterson

You using a hose with muffs?
How's the water pressure?

Or a bucket?
The bucket, the lower unit needs to be DEEP
in the bucket. 4" over the cavitation plate.

How long you running before shutting it off for
no flow?

Hi Jerry and thank you for responding,

We tried the muffs but considered the use of a large full tank to be better so that is what we did and we let it run with the thermostat housing open but to no avail. We have now stripped it down again and we have the lower end in the vice and we have checked the impeller housing once again and fitted a new gasket then rebuilt it.

We are about to fit a small plastic extension tube to the existing white outflow tube from the impeller housing simply to make sure that we are getting a good fit to the male pipe in the engine bay but as we have found no good reason for the lack of water circulation we are stuck and I am not optimistic that this will change anything.

have you encountered this before??

Best Regards
Bill

Again how deep in the bucket or tank??
It needs to be 4" over the cavitation plate.
Go back to the muffs if you have adequate
water pressure, the stronger the better.
If they don't seal very good? I use duct tape
and tape them in place.

The missing thermostat?? some people think
you don't need one. But it's a necessary
piece of equipment.
If the motor runs below the set temp 110d
it won't run as good as it should, uses more
fuel too.

Post a pic of the pump housing, inside and out
and the wear plate.
What impeller did you buy? Part#??
They used one for the 85 and 125 then changed
to a smaller one for the newer motors.

Hi Jerry and thank you for your perseverance. You will not be surprised that you were correct in your assumptions relating to the depth of the tank as we thought that it was deep enough so we tried the muffs and taped them on all to no avail, however, we decided to wedge the tank up to be tight on the sked and then to fill it to the absolute brim and leave the water hose running and "hey presto" it circulated water through all the important places so thank you once again.

As one door closes another slams in your face so imagine my disappointment when we were unable to get the trim motor to raise or lower the engine after it working previously having ordered and fitted 2 new regulators. We topped up the hydrophilic fluid but no action so we changed the battery to make sure it was fully charged and still nothing even though the engine was running satisfactorily. Is there a cut out I have missed or do you know of any other reason that it should appear dead after working so successfully previously?

Hopefully this will be that last hitch and I will be able to get it launched before winter sets in.

Best Regards
Bill P

There's your problem, you used hydrophilic fluid. You want hydrophobic...
Sorry, couldn't help it...

That was a typo via the internet, What I meant to type was the generic word "Hydrolic" but what was in fact used was Quicksilver marine Lubricants Power Trim & steering fluid which i believe fits the bill !!

The 1988 85/125 and ALL Prestolite T@T systems
use 30w oil. They used the Prestolite system until
the early 90's then went to a mercury pump and
Prestolite rams. Fill it while the motor is in the down
position.

The red oils won't stop them from running, just the
life expectancy is shortened.

Now? why won't it work?
Does the motor turn?

The new "regulators" ?
Relays and their connections.
The connectors are famous for poor connections
and cleaning with carb cleaner and squeezing the
connectors to make them fit tighter on the relays.
The relay setup was poorly designed and outdated
the day it was introduced.

The motor should have 2 wires.
Unhook from the relays and test them on a battery.
One lead on + and the other on - that should make
the motor do something.
The blue lead is for up, the green is down.

If this doesn't move the motor.
Then under the cap on the motor one of the wires has
probably a broken connection???

Thank you Jerry

I will get on it on Monday morning.

Regards
Bill

Hi Jerry

I drained the trim motor and stripped it down then I cleaned and undercut the commutator, rebuilt it and filled it with new 30W hydrolic oil.

All is now working well and the boat is finished just in time to lay it up for the winter.

Thank you once again for all your help and advice which has been invaluable.

Best Regards from Scotland
Bill

It's 30w motor oil.
Enjoy the winter.