cheap charlie Posted July 16, 2012 Share Posted July 16, 2012 Hi All, I purchased a boat a couple of months ago with a 98 model Johnson (OMC era) 70hp VRO. I purchased the boat from a dealer who told me they had been servicing the boat for years and that they had changed the impeller amongst other items. ( I did not think to ask exactly when it was changed). Every thing seemed well and the tell tale pumped water etc. my mate has a BRP 40HP Johnson and I noticed the flow rate from his tell tale was considerably more substantial with a much higher degree of pressure. Comparing the flow rate of my outboard it appeared to have 30 - 50% of the flow & pressure of my mates. First thing I did was to rig the garden hose to the teltale to eliminate a possible restriction. The flow increased a little but not by a great deal. I then got the compressor out and stuck a fitting into the teltale hose and gave it a good blow out, repeated with the water and back to the air again. Cleaned out the telltale L shaped fitting also. The next port of call was the Thermostat, a little bit of a salt build up in the housing but not as much as I would have expected. removed it and heated it in water to check it's function. It opened but would not close, even after soaking it in cold water for 5 minutes. Thats and easy one, thermostat added to my shopping list. Having a look around I pulled the spring out that sits between the thermostat and the head. 2 or 3 balls of deformed black rubber where in there. Thinking it was the remains of the impeller I dropped the leg of. Noticed the pump cover looked to be reasonably new and was coated with lube on the joints of the pressure side of the cover. removed the cover and the impeller looks new with the ribs still present on the outer surface that rubs on the wall and also felt reasonably firm. (Refer Pics). I had been told the impeller was replaced and it certainly looked like it was recently as there was no real built up of crap on the covers etc. Grabbing the air nozzle I gave the pick up a good blast and there did not look to really be any thing much in there. I gave the section where the water feeds into the impeller a blast out and out shot more balls of rubber from presumably a old impeller. Is there any thing i have missed? Ideally I would reassembly and test the water flow rate out now, but I want to avoid having to pull the leg back of again If there is some thing else that needs to be checked whilst there. Any Suggestions? Link to comment Share on other sites More sharing options...
Testlab Posted July 16, 2012 Share Posted July 16, 2012 Maybe put the hose in the thermostat hole and see if anything comes back out the pipe from pump to block. If there is bits of impellor up near the thermostat it could be in the tube too. Other than that, sounds OK to me. Link to comment Share on other sites More sharing options...
cheap charlie Posted July 16, 2012 Author Share Posted July 16, 2012 Maybe put the hose in the thermostat hole and see if anything comes back out the pipe from pump to block. If there is bits of impellor up near the thermostat it could be in the tube too. Other than that, sounds OK to me. Testlab, thank you for answering to all my posts! A good tip on flushing thru the thermostat housing and I will be definitely doing that. Should I shell out on a new impeller or would I be able to get away with the current one? Link to comment Share on other sites More sharing options...
Plumb Posted July 16, 2012 Share Posted July 16, 2012 I had issue with my Johnson 2005, turned out to be just the ear muffs, get a large enough bucket and submersed the whole leg and see how it goes. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
cheap charlie Posted July 16, 2012 Author Share Posted July 16, 2012 Thanks Plumb, I had that issue with an 08 Suzuki 30HP. The issue I have is present on the muffs and with the leg submerged. Link to comment Share on other sites More sharing options...
Guest Aussie007 Posted July 19, 2012 Share Posted July 19, 2012 are u comparing a Etec 40hp to a older model OMC 70hp? while u have the leg off lift up the impeller and check the key isnt broken and if your engine isnt over heating theirs nothing wrong with it Link to comment Share on other sites More sharing options...
cheap charlie Posted July 19, 2012 Author Share Posted July 19, 2012 are u comparing a Etec 40hp to a older model OMC 70hp? while u have the leg off lift up the impeller and check the key isnt broken and if your engine isnt over heating theirs nothing wrong with it Hey Gazza, No was a 40HP carbied 2 stroker. I was also comparing it with other motors i have had previously. The key is intact. As I bought the boat recently from a dealer, they offered to send me out a impeller and thermostat. Even thoe the impeller looks fine I will just change it over given the zero cost and that way it illuminates the impeller and I am confident in just how old my impeller is going forward. What have you been up to Gazza? Any project motors on the go? Link to comment Share on other sites More sharing options...
Guest Aussie007 Posted July 19, 2012 Share Posted July 19, 2012 when u have the lower leg off connect a hose to the water intake pipe that your water pump connects to turn the tap on only gently and see how it pees and look up inside the exhaust tube to see if the top seal on the intake pipe is leaking this is a common problem and reduces the water flow as it just leaks from the seal part number 21 http://www.crowleymarine.com/johnson-evinrude/parts/52584.cfm i hope for your sake it isnt this seal can be a pain in the ass to change and might need the powerhead removed nah mate no projects on the go yet still enjoying my mercury the fuel savings,the quietness and no smoke all though i did find a ripper of a engine on online shop it was a 1998 tohatsu 30hp 4 stroke i got outbided in the last 4 seconds by $2.50 Link to comment Share on other sites More sharing options...
cheap charlie Posted July 19, 2012 Author Share Posted July 19, 2012 when u have the lower leg off connect a hose to the water intake pipe that your water pump connects to turn the tap on only gently and see how it pees and look up inside the exhaust tube to see if the top seal on the intake pipe is leaking this is a common problem and reduces the water flow as it just leaks from the seal part number 21 http://www.crowleymarine.com/johnson-evinrude/parts/52584.cfm i hope for your sake it isnt this seal can be a pain in the ass to change and might need the powerhead removed Nice Tip, I will be sure to test that seal. Thanks Again Link to comment Share on other sites More sharing options...
Guest Aussie007 Posted August 3, 2012 Share Posted August 3, 2012 Charlie have u found the problem yet? Link to comment Share on other sites More sharing options...
cheap charlie Posted August 3, 2012 Author Share Posted August 3, 2012 Hi Gazza, All sorted that mate. Link to comment Share on other sites More sharing options...
Guest Aussie007 Posted August 3, 2012 Share Posted August 3, 2012 what was the problem? Link to comment Share on other sites More sharing options...
cheap charlie Posted August 3, 2012 Author Share Posted August 3, 2012 I found noting that was definitively the cause of the issue, but i found bits of an old impeller in behind the thermostat and also some jammed up under the induction point of the water pump. The bits of old impeller was not from the impeller that was currently fitted as it was intact. In the end i flushed the crap out of every thing I could, new thermostat and impeller. After dummy fitting the leg I connected up the gear linkage and ran the motor from forward thru reverse etc and was horrified to find I had no reverse. After thinking for a bit I wondered if the rod was threaded into the gear box. Dropped the leg to the end of the bolts, couple of turns of the shift rod did the trick. I must have spun the rod a couple of turns whilst i had it apart. Lernt a couple of new things along the way. After all that the boats going on the market. I bought a Hobie Kayak today Link to comment Share on other sites More sharing options...
Choicebro Posted August 3, 2012 Share Posted August 3, 2012 Mate, I don't reckon you'd have the same problem witht the Hobie.... So happy days... Cheers Kel Link to comment Share on other sites More sharing options...
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