130 degrees plus or minus 10.
Once opened (suspended on a string, NOT TOUCHING the pan), have a SEPARATE pan of cool water you submerse it into. Thermostat should close at or before 10 seconds (fully). If it does not, IT IS BAD.
Your problem isn't that it's overheating... but we need to make sure it's not running COOL/COLD as that can result in a rich condition on one bank of cylinders.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Well I tested all three I had. Had a spare and the spare and one of them I had on the motor took about 150 to open and didn’t seem to open as far as the other then the good one close in about 11 sec in water others took a min in water and then I sat them on the counter and had to pop them closed so I’d say they are bad. Hopefully this fixes the problem
should do it
.................................................. ...the scariest thing in life is the unknown ...................................
Amazes me how many of the "how to's" completely overlook the CLOSING cycle of the thermostat.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Agree. Thanks guys. Hopefully this fixes the issue. I have them ordered and will post once I get them and run it on the water.
So fished a tournament today. Once again first start up and idle of the day is good. After that it died all day when put into gear unless I give it throttle right away. Is there an idle air control valve or something similar that could be causing this issue. At about 1000 rpm’s it idles fine.
There is no IAC on the Optimax models.
Check shift position switch to make sure it's working correctly.
If it is, check the air/fuel pressures, as well as throttle plate air gap.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Ok I’ll check those asap. Wouldn’t u think if it’s the shift sensor it would always do it. It deff seems heat sensitive as it never does this on the original start up of the day
I guess if it’s going bad the heat could affect it. What’s the steps to check the sensor. ?
just unplug it , go run it
.................................................. ...the scariest thing in life is the unknown ...................................
In neutral it was zero and in gear it didn’t change on an ohm test. Wouldn’t running it unplugged cause it to shift hard
shouldn't , just doing a test anyway
.................................................. ...the scariest thing in life is the unknown ...................................
Concern would be coming OUT of gear (just be careful if trying to dock). If it did not change (ie: Continuity regardless of whether in neutral or in gear), replace switch.
Make sure the throttle cable end nut isn't over-tightened, too (threaded nut should be snug, then back off 3/4 - 1 turn so the plastic washer can spin freely). Too tight causes slide to bind and breaks/damages shift switch.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Finally got part and installed. Haven’t been able to run it yet so we will see.
Well finally was able to run it today and it’s still wanting to and dying when put into gear and not giving it throttle. If I give it throttle it will stay running and runs good other than that. This is really getting annoying. I’m going to try and get to the shop again but nobody close so not sure when I can. Any other advise would be great
how many hours did you say were on that powerhead /fuel system , when did this problem start , possible pcm or injector lean condition at idle , air psi volume test preformed ?????
.................................................. ...the scariest thing in life is the unknown ...................................
Roughly 400hrs. The shop was supposedly contacting Mercury to see if the pcm needed re flashed. 2 months and they haven’t heard back. Started this season. Runs fine on hose and ran fine while at the shop zero issue said everything was reading good at idle except water pressure was just a touch low. Since I have changed water pump,pulse pump rebuild,thermostats,neutral switch,plugs and wires issue is still their and it Only acts up when put in gear at idle.
Air test was mentioned to the tech but he said everything was good on readouts so I wasn’t going to ? The guy who does it everyday
What is the water pressure at idle in gear now?Originally Posted by RBwd8506
check compression on this motor if any cylinder is down by more than 5 psi perform a leak down test on it.
Recheck air/fuel pressures and leak down rates.
send fuel rails to Don for evaluation
Thank You Leon Pugh
Water pressure is good and I don’t see what that would have to do with dying when shifting into gear. And if compression was off I’d think it would run rough at idle or in gear. I plan on having them check fuel and air pressure when I can get it to them
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