Harry S Posted May 2, 2006 Report Share Posted May 2, 2006 I have a 5 year old Mariner 60hp 2 stroke on a Warrior 165. Have used the boat a couple of times in a variety of conditions and didn't notice anything untoward until last weekend. Launched from Wick and engine started first time. Slowly motored out towards sea at 4 knots for 30 minutes and then went at 20 knots for 20 -25 minutes until joining Neo and dropping the anchor. Left motor idling for about 10 - 15 minutes and the engine warning buzzer went off. Noticed slightly more than usual exhaust smoke but put this down to the fact that the engine was still trimmed up a bit. Visibly, the tell tale was performing OK. Switched off engine. Tried not to panic. Fished for about an hour or so and then decided to move off. Engine started first time, tell tale OK, no buzzer and so set off at 20 knots for about 15 minutes. Dropped anchor and then checked tell tale. Nearly scalded myself. Switched off engine. Beginning to think there may be a problem. After another hour, engine started OK and so cut anchor warp (another story) and headed back to Christchurch following Neo at about 15-20 knots and then 4 - 8 knots back to Wick. Tell tale working OK. No more buzzer. Switched off as soon as reached slipway. Next day put on engine muffs at home and flushed out with fresh water. Tell tale temperature was cool at tick over at 800 rpm for 15 minutes or so but rapidly became very hot at 2000 rpm. Is all of this normal? Am I paranoid? Is there a problem? The only thing I did to the engine before this particular trip was to top up the 2 stroke oil resevoir with Quicksilver 2 stroke oil where I noticed that the new oil was a darker blue than that which was already in the tank. Any advice/reassurance greatly appreciated. Harry Quote Link to comment Share on other sites More sharing options...
Afishionado Posted May 2, 2006 Report Share Posted May 2, 2006 A common cause of these symptoms after a period of inactivity over the winter months is a sticky thermostat. At low speeds even the restricted flow through a closed thermostat will be sufficient to cool the engine. However more throttle will create more heat which needs a greater flow of water to cool the engine. I would sugest removing the thermostat and then re run the engine at home to check the running temp' with it out. It is perfectly OK to run the engine with no thermostat at all, in fact I have removed mine due to a similar problem last year. If you need a mobile O/B mechanic to call and sort it, I can thoroughly recommend Sam 07810 561520. Mad Mike Quote Link to comment Share on other sites More sharing options...
Harry S Posted May 4, 2006 Author Report Share Posted May 4, 2006 Thanks for the advice Mike. Does anyone have a worksop manual on CD who could email me the page dealing with the thermostat on a Mariner 60hp Bigfoot? Quote Link to comment Share on other sites More sharing options...
plaicemat Posted May 4, 2006 Report Share Posted May 4, 2006 Harry, I have a manual for that engine, it being the same as mine. I'm not a million miles away from you and you're welcome to borrow it if you so desire. Terry B. Quote Link to comment Share on other sites More sharing options...
Harry S Posted May 4, 2006 Author Report Share Posted May 4, 2006 Thanks for the reply Terry. I have the owners manual in forty languages but it doesn't go down to the detail of changing a thermostat etc. I need the equivalent of a Haynes Workshop Manual - or an expert! All the best, Harry Quote Link to comment Share on other sites More sharing options...
plaicemat Posted May 4, 2006 Report Share Posted May 4, 2006 O/k, simple job. The thermostat is on the left hand (facing front) top of the cylinder block under a black cover with 3 bolts holding it. Pop it out and put it in a pan of water, bring to the boil and see if it opens. If not, it is kna**ered. If it does open, remove from hot water and see how long it takes to close. To replace it, you will also need the thermostat housing gasket as well. Both items can be obtained from Redline Outboards, Abingdon. Give them a call and ask for Mike. Terry B. Quote Link to comment Share on other sites More sharing options...
Seamouse Posted May 4, 2006 Report Share Posted May 4, 2006 Try the same query on the WSF site (http://www.worldseafishing.com/). They have a very active technical forum. Steve Quote Link to comment Share on other sites More sharing options...
britboard Posted May 4, 2006 Report Share Posted May 4, 2006 It is perfectly OK to run the engine with no thermostat at all, in fact I have removed mine due to a similar problem last year. In my personal experience as a two-stroke and 4-stroke tuner for both aviation and racing engines, i would suggest you would be ill advised to remove the thermostat and run the engine for anything other than test purposes. Reasons being that you would have an engine that is running cooler than it was designed to, this will lead to increased wear of both pistons,rings and cylinder bores as the clearances would be reduced, the two stroke oil will not be as efficient as it will be more viscous (thicker) causing more resistance creating larger amounts of stress on all the engine components and a reduced ability to find the smaller crevices and meaning you will have to give more throttle to compensate for this, so you will burn more fuel. You will have to de-coke on a more regular basis as the burn process will be less effiecient leaving more deposits. also a warning about mixing 2-stroke oils i would always use the same brand and type of oil as i have seen oil emulisfy when mixing brands, which can lead to catastrophic failure due to lack of lubrication. Always mix a small amount in a pot and leave it for a day or two to see what happens before you fill the tank, its very rarely a problem but once its in the engine its a much bigger problem. The same advice stands for 4-strokes except that the oil is in the sump and used for lubrication only and not mixed at the inlet manifold (with the fuel) as a part of the power cycle. sorry for the essay, but its my subject I'm out from christchurch on saturday with Alun J if you want me to take a look or give me a shout as i'm based in High Wycombe Simon L Quote Link to comment Share on other sites More sharing options...
Fugazi Posted May 4, 2006 Report Share Posted May 4, 2006 Simon, If you Quote Link to comment Share on other sites More sharing options...
Coddy Posted May 4, 2006 Report Share Posted May 4, 2006 Hope to be out there on Staurday as well Will follow and watch the master at work! Coddy Quote Link to comment Share on other sites More sharing options...
plaicemat Posted May 5, 2006 Report Share Posted May 5, 2006 Looks like being busy, I'm out as well. Terry B. Quote Link to comment Share on other sites More sharing options...
alun j. Posted May 5, 2006 Report Share Posted May 5, 2006 Hey ! Stop this ! It's just about having some bait out in the water..... and 'sensing' when you're in the wrong spot......and when to move. ..........and it doesn't always work .......... does it James ?? Looking forward to this weekend........ fingers crossed that it turns out as calm as forecasts indicate ........ then we can concentrate on the fishing. Plenty of spots to choose from...... Tight lines, Alun. Quote Link to comment Share on other sites More sharing options...
Fugazi Posted May 5, 2006 Report Share Posted May 5, 2006 Alun, There's no need to be modest with all this being in the right place stuff, I was in the same place, on the same boat and I couldn't match your success rate. Just accept that if the cap fits you have to wear it and know that I'm expecting great things from you tomorrow. No pressure, Gordon H Quote Link to comment Share on other sites More sharing options...
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