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Chrysler 135hp - removal of water pump housing

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  • Chrysler 135hp - removal of water pump housing

    Hi there,

    I'm very new to this site and will probably be on here quite a bit from now on. Based in Dunedin New Zealand on the Otago peninsula I have a pretty old Dominator with a 135hp Chrysler.

    The engine has not been run for a couple of myears now although has been kept under cover. With summer upon us I thought it would be great to get it out. Engine fired up first time, but I noticed almost right away that there was no water pumping out. Could be any number of things I guess, but first thought was to look at the water pump/impeller. I have the lower unit removed. The water pump housing has 4 ratyher large screw heads that app-ear as though they have never been removed. Thjis is a little surprising as I think the engine is 1976/7.

    I have attempted to remove these screws - no chance, they are well and truely secure. Does anyone have a suggestion on how I might easily free them without causing damage? I have the screws soaking with WD40 for now and will have a go with freeze free or similar tomorrow. I'm sure there must be an easy way to get these beasts out.



  • #2
    Re: Chrysler 135hp - removal of water pump housing

    Well, Shane,First--Welcome to the forum. This seems to be the year for Kiwis and Aussies on the forum.

    Now: Unfortunately, whether you have a one piece lower unit (up until 1977) or a two piece lower unit (after 1977) The penetrant will do little if any good. The screws go down through the water pump and corrode not only inside the pump casting but inside the lower unit casting as well. There is no easy way to remove them and if you snap them, you are in for a truly long and miserable job.

    You can continue to soak them in the hopes that some penetrant will get in or you can try heating the pump body and the lower unit casting. This, however WILL ruin the impeller and the upper drive shaft seal.

    The bolts are 1/4 X 20 with a 7/16 inch head. You can try an impact wrench or try "wiggling" them out. Since it is boating season down there, my suggestion would be to find a better used lower unit to install while you work on this one.

    Post a couple of photos of the engine and the lower unit so we can better tell what year the engine is.


    • #3
      Re: Chrysler 135hp - removal of water pump housing

      One of my 105's had hex head 1/4-20 bolts, whereas the other had slotted head countersunk 1/4-20
      screws, the latter arguably more difficult to apply massive amounts of torque to. If they won't budge no matter how hard you try, you could resort to center punching and drilling off the heads, after which you may be able to encourage the pump housing up (a little persuasion with a mallet and putty knife), depending how much corrosion has built up around the screw shanks and housing. If the housing lifts off, the remains of the screws should yield to vise-grips. If the housing doesn't survive the extrication process - well, it isn't doing you any good as it is! Good luck.


      • #4
        Re: Chrysler 135hp - removal of water pump housing

        Many thanks for the answers, sounds like I am in for a rough time with this unit. It's dark at the moment so I'll post some engine pictures tomorrow. The lower unit came off as one piece by removing six bolts and of course disconnecting the gear rod. The gear box does appear to be a seperate unit - the separation is clear but the connecting bolts/screws are not clear?

        I ran a hose into the water pipe to check that water was going up into the head and out as expected with the engine running. Pretty strange really - it did splutter out but not as much as I was expecting. I removed the top thermostat and the water gushed out the top but still little coming from the outlet port. I also had a quick look at the bypass - spring intact and little corroion. Not sure I understand what this bypass thing is for or how it works, it seems passive to me as if it can only be in one position permanently? Even with the hose going and some water coming from the outlet port I suspect the engine is overgeating. It is not shutting down but the head certainly becomes un comfortable to touch.

        I tried using an impact driver today on the pump housing screws. Again not so much as a budge of movement - pretty much what you have said. There's little or no chance of finding another lower unit here in NZ, so I'll be stuck trying to get this machine into the water unless I put it aside and get something smaller for the time being.

        I'll continue with another penetrating oil for a few more days and perhaps resort to drilling them out later in the week - not looking forward to that though.

        Pictures to follow, thanks again,



        • #5
          Re: Chrysler 135hp - removal of water pump housing

          There should have been a seventh bolt inside the exhaust snout. If you have the two piece lower unit, it will have 18 splines on the prop shaft and a thrust pin in the prop hub. This is held in place by the tailcone. If you do have the two piece lower unit, there are either two or three nuts on studs holding it together. One up top in the nose and two behind the water pump. However, you should not need to take it apart.

          If you do need to drill out the water pump bolts, three are OK to go deeper and re-tap however the one in the front on the vent side will enter the case at the vent threads if you go too deep. So be careful.

          The exhaust downtube has a gasket below a flange. If this gasket is worn or missing, water will just drop out the leg and very little will exit the idle relief vents.

          The bypass was a nicety but not a necessity and was discontinued in later Force engines. When the thermostst is closed, excess pressure forces it open against the spring and bleeds excess water back into the leg.

          The head should be uncomfortably hot to touch, you would not be able to leave your hand on it, but a couple of drops of water should not boil off it.


          • #6
            Re: Chrysler 135hp - removal of water pump housing

            Hey Shane

            My 2 cents for what its worth- seeing as though the ANZAC's are taking over the forum!

            I have a 125hp Force 1988. When I bought it, I joined the forum, and was convinced by Frank and co to work on it myself. I am a little handy, but no mechanic. Currently, I am doing the idle etc, but thats beside the point.

            When I removed my exhaust plate, I was warned about snapping bolts and a hard time, and I was lucky to have snapped just 1. Things may not be as bad as they seem with your lower unit. It took me 2 weeks to remove my exhaust plate, with WD40, and a little friendly persuasion, we got there. Good luck with your waterpump, and scan ebay!!

            You will never 'meet' a more knowledgable bunch of guys who are happy to help, than on this forum. My boat is dependable, reliable, and best of all I can work on it myself.

            Welcome to the best forum on the web ( IMHO). Lets start a fishing comp online- between those darn Yanks and the ANZAC's!!

            Make sure you start with the simple things first.Ask yourself- " IS MY BATTERY CONNECTED"


            • #7
              Re: Chrysler 135hp - removal of water pump housing

              Hey guys,

              Many thanks again for the comments and feedback. Not having much success with file uploads here at the moment so I've posted some shots to the following site:


              There vare a few of the lower unit, the engine, and one of the serial badge - I think the numbers should be clear enough to read.

              Frank, you are spot on about the 2 piece LU - I suspect someone has left out that 7th bolt, but I do have the 18 splines on the prop shaft and the mentioned thrust pin. The prop is remarkably easy to remove - I wish the other parts were so simple. Thanks for clearing up that bypass thing, makes more sense now. I'm intrigued about the exhaust downtube and gasket mentioned. Do I need to remove the engine head to gain access to this? From reading other threads I had assumed you should be able to touch the head while running - great to know there may not be an issue afterall. But I think it will be best to continue with the pump anyway and ensure it is actually operational.

              I did have thoughts of leaving it into a marine shop but I would love to be able to get this running myself. Thank you for the encouragement.

              As for the fishing comp - you do kinow that in NZ waters we spend most of our time fighting the fish and very little waiting about. May not be much of a competition :-)

              Cheers Shane


              • #8
                Re: Chrysler 135hp - removal of water pump housing

                I have just come upon a Chrysler 120 going for what seems to be a really cheap price. I have only seen some pictures, but the physical aspects of the lower unit, leg and cover appear just like the 135. It is complete and reported to be running well. Would this be worth having for part for the 135? Engine looks identical apart from the head plate. Lower unit has also had the impelloor replaced, means they must have had easy access to thge pump. Just a thought but would welcome words from the experts. I suspect the package price would be less then the labour charge for the 135 if I left it into a shop.

                Cheers Shane


                • #9
                  Re: Chrysler 135hp - removal of water pump housing

                  Pretty sure that L/U will bolt right up to your stove. Frank will be able to confirm that for you. The 120 was advertized as having the impeller replaced - probably worth to at least pull the housing and eyeball the impeller just to make sure the rubber vanes aren't cracked, if not slip a new one in to be sure.

                  Justin had a comment about a friendly competition ANZAC's vs. Yanks. Where does a Canadian fit in Eh?


                  • #10
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                    Re: Chrysler 135hp - removal of water pump housing

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                    First, I don't know how it is down there, but up here you would not be able to get a mechanic to work on your engine. So: Don't bother taking it to a shop because even if they decide to do it, the labor charges will kill you and you may get a poor job to boot.

                    The difference between the 135 and the 120 is the size of the piston, (3.375 vs 3.3125), carbs, and the port timing. Aside from the pistons, everything else is swappable--assuming as you said that the lower units look the same.

                    leave the exhaust downtube alone. It requires removing the complete powerhead and even if the foam gasket is broken or missing, it will not affect operation of the engine.

                    As far as temperature: Remember that your home hotwater is set to 125-135 to avoid scalding you. The engine runs at 165-185 so you figure. Your block has been replaced since it has no paint. There is a possibility that originally the engine had the poor Magna-Power II ignition and was retrofit to distributor Motorola. The clue is the coil mounting bosses on the head. I can not tell from the photo, but if they are threaded, then the ignition was changed if they are not threaded, then the engine came that way with that head. I also noticed that it appears that the overheat switch just above #2 plug appears to be broken--difficult to see from those photos.

                    It also appears that the power tilt was added later. There is a tilt lock plate in the last photo---get rid of it. It does not belong on power tilt systems and certainly is not strong enough to withstand trailering stresses. Either get a transom saver or make a trailering bar like these.The bar in the last photo is made from square tubing and 1/2 inch rod. Either was stock and either will withstand trailering.

                    Since Chrysler changed to a one piece lower unit in 1979, and since you have the later model lower unit, it would appear that your engine is somewhere around 76-78.

                    I have included a couple of photos of what your lower unit looks like disassembled.