impeller?????

[johnjay28]

i recently replaced the impeller on my rde-17 johnson. the old impeller was in shreads when i removed it. i figured it was turning clockwise so i bent the tips to the left. will the tips self align after it runs or do they have to be installed a certain way. i started the motor with water above the inlets but only let it run for about 5 sec. i did not see any water come out of the water outlet. did i not let the motor run long enough or is the impeller in backwards.thanks for your help. john

 

[Paul Moir]

Re: impeller?????

Those long-vaned OMC impellers will flip over the right way the moment you start the engine if you install them backwards. So it really doesn't matter if that's what happened.<br />Since your engine doesn't have a thermostat, water should have come out the large hole in the back the moment the block filled. I'm afraid you'll have to remove the lower unit again and find out what went wrong. Possible problems are:<br />1) Impeller key fell out of driveshaft when you installed the impeller.<br />2) Water tube is not lined up with water pump outlet.<br />3) A bit of the old impeller is clogging up the cooling system.<br /><br />If it turns out to be #3, then you can try hooking the water tube up to a fawcet via a lenght of hose. Then use street pressure to blow out the impeller bits. Failing that, it's time to start disassembling stuff.<br /><br />Good luck!

 

[johnjay28]

Re: impeller?????

thanks paul, for the info. this will keep me busy this weekend unless i have time before. i'll post my findings. john

 

[SpamPutney]

Re: impeller?????

Before you do any major disassembly, remove the end of the telltale. What I mean is, if you open the hood, you should see some rubber tubing leading to the telltale. Bits of rubber can get jammed in the nozzle (not sure if this is what its called). By removing the nozzle, the diameter of the hose is wider and may allow the bits out. Try blowing some compressed air in the hose...may dislodge anything stuck in there. Then, try to "prime" the engine with water by attaching the ears and running the water for a minute or so. Crank it by hand, slowly for a few turns. Then try running it again. No more than 5 secs or so. If that doesn't work, you will need to disassemble again. Good luck!!

 

[johnjay28]

Re: impeller?????

idropped the lower unit on this 1955 rde-17s and flushed out the water tube with a hose that fit snugley inside the tube water came out the discharge end and the pee hole also some water was coming out from inside the unit where the shifting linkage is located. perhaps the tube is not sealed at the top? is this normal? the water inlet up to the pump is clear. is there suppose to be any sealant applied to the bottom of the stainless steel plate where the impeller rides? also on the lower unit where it bolts on to the upper unit.i don't see any thing else that might that might prevent the pump from sucking water from the inlets. perhaps i was in to low of RPM's if someone has any ideas please let me know. i a ready to install the lower unit thanks. john

 

[johnjay28]

Re: impeller?????

BTW this is a 25 hp. the pin on the shaft is ok and does engage the empeller. another thing i did was lay the unit on its side and slowley pour water in the inlet and when i rotated the shaft it would pump water out of the pump. i used vice grips on the shaft after wrapping it with some rubber in order to not damage the splines. john.

 

[Paul Moir]

Re: impeller?????

Spamputney - this engine has no tell tale like you've seen. Rather it has a water outlet.<br /><br />Johnjay - Way up in the water outlet hole above the two small holes is a much larger one which will let water into the midsection. If it seems to be concentated to the back of the chamber (ie, on the water outlet side) this is what your seeing. If you look up the midsection along the back wall, you'll see a square hole up into the chamber where the hole to the water outlet is.<br />If that's not the case, then you may have a leak. Break out the flashlight and try to figure out where the leak is coming from before you start hauling it apart.<br /><br />Whether or not you put sealant on the bottom of the stainless wear plate between it and the lower unit is a matter for debate around here. I seal mine though (using Permatex #3 aviation form-a-sealant rather than RTV) and seem to draw water fine. Lots of people don't though and I guess it works for them. No sealant or gasket goes between the lower unit and the mid-section.<br /><br />The waterline must be up to the pump at idle. Once your speed picks up water is being forced into the pump by the propeller. At that time, the whole leg will be pretty well empty of water and full of exhaust.<br /><br />Don't forget to grease the driveshaft before reinstalling. It makes all the difference in the world when you go to take it apart again. Use a little sealant on the lower unit bolts' threads and they'll come apart much easier next time.<br /><br />Good luck!

 

[johnjay28]

Re: impeller?????

first of all i want to thank all of you for taking your time in helping me with my two posts "no spark, and empeller???? " i followed your advice and the motor is now running and peeing like it drank a keg of BUD. thanks again, john also iboats for the parts for this old motor.