1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

[Coop10]

This is my maiden voyage on this site.

I have purchased my first boat that also came with my first outboard motor. The boat is a 1963 MFG Niagara Runabout and the motor is a 50 HP US Marine Force. I am aware that neither of these are quality items but I did pick them up with a trailer for $350.00.

Now on to my question. I put the motor in a tub making sure that the inlets were covered and started the motor. I had changed the plugs just prior and the motor started up after a few cranks. It ran for a bit (rough as it was) and then stalled. As it was running, I checked to see if water was coming out of the discharges and there was none. I believe that the motor was under the water far enough since it was just over the planer fins. does this mean that I have a water pump issue? I have researched on line and see quite a few listings for changing the impeller. Is this the likely reason for the stalling and hot motor? Does changing the impeller usually do the trick if it is the problem or is there a complete rebuild of the water pump that is in my future?

Thank you for any help that you folks can offer.

 

[foodfisher]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

Yes to all the above. A problem could be if parts of the ruined impeller are blocking the passages. Running in a bucket, the deeper the better.

 

[DAN M VAGOS]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

Hi I have the same motor on my bayliner and the motor will not spit water for like a 20 seconds. So how long did yours run for and yes if the water is over the cavitation plate you are good. I can tell you that doing the water pump is not hard but on a old motor it's not fun. My water tube came out of the head witch it's not supposed to do so I had to Ginny rig it but it works.

 

[DAN M VAGOS]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

If you do need to change the impeller just remove the bolts under the cavitation plate then the shift rod coupler and the lower leg will come right off. Then the bolts for the impeller just remember witch way the fins are facing and don't forget the key way. After that put it all back together and try it. It's really not bad at all.

 

[Coop10]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

Thank you to all for the prompt replies. It is good to know that there are knowledgeable individuals out there that are willing to share what is, most likely, years of experience with those who have hours worth of experience.

Not to beat a dead horse (or Force as the case may be) but is there a way to troubleshoot the water pump or impeller first without the need to drop the lower unit? I am pretty sure that I can change the impeller if need be but I would prefer not to open up that can of worms unless absolutely necessary. The other issue with which I am faced is that I am unsure where to find said impeller since the motor is such an early model. Any clues?

Thanks again.

 

[foodfisher]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

You can install a telltale, and know the pump is pumping.

 

[Coop10]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

I have seen these installed on videos on the web but that may be a step above in expertise than even changing the impeller. At least most of the parts are big with the impeller, I am not quite sure which screw or bolt to remove to install the telltail.

 

[scottmm73]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

Coop, purchasing a manufacturers maintenance manual is worth its weight in gold when it comes to these Force motors. They are a very simple motor and actually very easy to work on.

With that being said, may I ask where your location is because there are quite a few Force enthusiasts that frequent this site and may be nearby to give you a helping hand.

 

[Coop10]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

I am in Cleveland, OH. Where can I find the manual? I thought I saw one on this site but with all of the page jumping that I have been doing it is all starting to run together making me a bit bumfuzzled at present.

 

[foodfisher]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

I have seen these installed on videos on the web but that may be a step above in expertise than even changing the impeller. At least most of the parts are big with the impeller, I am not quite sure which screw or bolt to remove to install the telltail.

Don't know the 50, on my 125 the thermostat housing had a plug/screw in it. Removed and replaced with a screw/barb elbow, tubing to the barb and routed conviently. That's it.

 

[Coop10]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

I see the manual up at the top of the thread so my first step should probably be to purchase that. Is the screw/barb elbow something that can be picked up at the local hardware store? Beyond that, if it turns out to be the impeller, is there a place to get that specific part?

 

[foodfisher]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

Elbow=yes. Impeller=yes. Probably here on iboats or a Merc. dealer

 

[Coop10]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

Sometimes it is just the little things. I removed the cavitation fins from the motor to enable me to submerge it farther into the tank (garbage can) as was suggested by foodfisher. I also used my garden hose to spay into the exhaust holes and back through the uptake tube. I started the motor and in a short period as described by Dan, the motor began to spit water out of the exhaust holes. I am not sure if the depth of the water or the flushing or both did it but it now works and actually runs well. I know our fire engines need primed before we are able to pump so maybe the water from the to assisted in being able to pull a vacuum. I will still purchase the manual as suggested by scottmm73 since, I am sure that this will not be the last issue that I have with a motor that is as old as my marriage (and just as confounding).

I want to express my gratitude for those on the site that are willing to share years of experience with those of us who have hours of it. I was a bit nervous when I bought the boat knowing that I had zero experience. I now am quite a bit less so with the knowledge that there are individuals out there that are willing to help.

Thanks,
Joe

 

[foodfisher]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

FYI: the pump pushes the water, won't pull.

 

[cbercaw]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

Get a Manual..search ebay for original force or a clymers manual. I have this same engine and have had lots of fun trouble shooting the cooling system on this beauty.. since this is a new engine to you i would: Buy a new thermostat and gaskets. Order a few impellers just to have on hand..Also, conditions unknown, buy two new water pump back plates F435562 and a woodruff key or two..they are all cheap parts and offer peace of mind. Replace the wear plate and impeller. Inspect your water pump housing for striations and signs of wear which can decrease pump efficiency.. Go to your auto parts store and get some Permatex 3H Aviation Form-A-Gasket..item 80019..Put a small amount on the mating surfaces of the water pump and leg..install a telltale as described above..use an 1/8" barb fitting attached to smaller vacuum line.

 

[cbercaw]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

you can get all of your telltale supplies at lowes or any hardware store (brass fittings) and an auto store for some small vacuum line..PM me if you like or just keep posting here, I have your same engine and I have rebuilt mine completely. the support on here is great. Everyone wants to help..again, Do not rely on an impeller that came with it..you need to change it..for the safety of the motor foremost and for your own experience..I have had impellers last for a year or more and i have had fresh ones break vanes only a couple of hours into there service.. I have a huge respect for these cooling systems..very temperamental.

 

[cbercaw]

Re: 1988 US Marine Force 50 HP outboard Motor Possible Water Pump Problem

chances are you have an original thermostat too. Replace it for 15$