8 hp Mairner "from last night"

[Lersia]

Motor idles fine and runs okay at mid trottle..... When I gas on it and run it full throttle,the problemn starts.... I hear a rattling sound right before it dies... Is something overheating ??? THANKS

 

[12Footer]

Re: 8 hp Mairner "from last night"

Yes, it could. As a motor overheats, the compression increases, the pistons build-up heat,and the gas detonates as soon as it comes in contact with them,causing a clatter or pinging.<br /><br />Can you see water exiting from the tell-tale?<br />Can you physicly touch the side of the block without getting burned, and is the paint blistering around the head?

 

[Lersia]

Re: 8 hp Mairner "from last night"

Yes, hot to the touch..... Water is comeing out of tell tell alot.... I just removed the thermostat to see if that might help.... Paint is chipping off of the top cylinder.... It has completely locked up once.... It still crakes up.... I have replaced the water pump and that works fine.... THANKS

 

[Johnshan]

Re: 8 hp Mairner "from last night"

My mariner 30 hp (1985) did this 2 days ago, overheated and seized but works fine once it cooled off.<br /><br />I had water comming from the tell tale hole just not a whole lot of pressure. Turns out when i dropped the lower unit the water pump lines up with a tube- theres a rubber sleeve there to avoid leaks and it got jammed up blocking like 60% of the water. <br /><br />If you serviced this area latley then maybe this could be your reason if you are overheating. <br /><br />This tell tale hole- is it truley a just to show you if theres water pumping? Or is this where all the water from the head exits? My friend tells me that hole is for the water exiting the head.<br /><br />Also i did not hear any rattles, but i to get a vibration at certain RPM's sounds like something in the flywheel.<br />-John

 

[Lersia]

Re: 8 hp Mairner "from last night"

Great New! I took out the thermostat.... Cranked the motor in a tank.... Wide open throttle for 5 minutes..... I was able to touch the block with my finger.... Bad thermostat!..... Now, I need to know can I run it a day with out one? THANKS EVERYBODY!

 

[rogerwa]

Re: 8 hp Mairner "from last night"

Just for kicks, you can very easily check your themostatic by sticking it in a pot of water with a thermometer and watch to see if it opens. This would be a good way to validate that the t-stat is bad without getting stuck on the water..