Mercruiser overheating at idle. 7 v8 Engine Overheating Symptoms: During 2020 we were out in our Bayliner 2855 (1994) trying to get her up on the plane, when we heard a loud siren go off from the dashboard. Boat overheating? Luckily we have only had to deal with this issue once aboard SV Sweet Ruca. 7L Merc I/O Overheats at idle. It was a surprise so I pass it along. Equipment: 1984 Sea Ray Monaco (purchased from the original owner in 1990); Mercruiser 5. Hello all. I have a 2005 Sea Ray with the 5. Click to expand 8) I have removed the thermostat and there is no issue with overheating. Ive tried 2 thermostats 140 and 160 still overheat after a couple minutes of running at any speed. Re: 350 Mag MPI Overheat at Idle I would be suspect of the raw water pump housing itself since you are getting a low pressure alarm as well as an overheat. The Mercruiser stern drive is one of the most popular marine propulsion systems on the water. I really want to run a thermostat so i don't get Water pressure is 0. I have re-powered this summer with the 5. General Q & A - Mercruiser Overheating (so am I) - The boat is out of the water. To be more specific: when running cruise and wot the temp is steady 71-73 degrees C (160-165F) but when returning at the dock and idles the temp raises till 85-88C (185-190F) not more. Water testing yesterday showed lower, and perfectly stable engine temp over a range of conditions. I shut her down checked the motor out, and nothing seemed amiss. I checked the impeller (new last year - less than 15 hours since) in the Alpha 1 Gen 2 lower leg and it's good as Overheating Troubleshoot - 4. The engine runs great at anything over 1400 RPM. <br /><br />I would make sure your water circulation pump belt is snug and not slipping. At idle for extended periods of time (5 min or more)engine temp will redline and temp alarm sounds. 3K views 14 replies 8 participants last post by Cast away nick Aug 28, 2018 Mini Yacht Discussion starter If the engine block is overheating faster than the exhaust manifold, I would probably guess you have raw circulating pump that has failed. 3 alpha 1 Gen II. Snailman<br />My boat has a flush hose connection to flush without useing muffs and a couple of times I have left the cap off. 4 Mercrusier Bravo 1 23 pitch prop low water pick up New hose between the out drive an the raw water pump New impeller New hose between the raw water pump and the oil cooler New Re: Mercruiser 260 HP OVERHEATING - Im Stumped! To check for them remove the exhaust rubber section and reach into the collector, on my 5. Idles perfect at 155 temp and under 3000 RPM before planing will run with a load and push water all day at 155. if your in salt water and the engine and drive are not flushed regularly, a build up of salt will insulate the block from the cooling water. Any suggestions? If your engine temp is OK at idle and slow speeds but when you get on plane you notice that the temp slowely keeps creeping up and up, you might have clogged and/or rusted exhaust manifold or riser water passages. Replaced the impellers and IAC valves this winter. When i swapped the impeller i noticed that it appeared to be in good condition, but the steel housing was pretty rough inside. Raw Re: 5. Feb 18, 2019 · I had this issue on my 8. Temp is normal if at 1000 or above. General Q & A - Mercruiser Overheat Problem - I bought my first boat. I have twin 4. 7, serial number 6732604 – with Alpha I outdrive. A Bayliner mechanic instructed me to change water impeller. Took the boat out this week and the overheating alarm went off after 4-5 minutes of idling. I cleaned it up real good and took it home and Hello, my 2009 350 mag mpi (1A348183) alpha one genii drive, running hot when it is on idle. If your engine is overheating turn it off and do not run it until you have fixed the problem. 3 overheats at idle only Ok, just back from a water test and unfortunately the problem is still the same! New impeller, thermostat and gear oil was done yesterday. 7L Mercruiser overheating problem?? I remember your last post you are on the right track right now getting a new T/housing as that can go bad at times and just to be as safe as you can by doing that. 2003 Sea Ray 280 w/ 4. This General Q & A - Overheat - How hot is too hot? - Had an impeller issue yesterday, overheated the motor (5. 3L Mercruiser engines - overheat at idle speed. Engine Overheat Troubleshooting Excessive overheating can ruin your engine. Temps are good ~170 when on plane or 7mph/1200-1500rpms. Re: 5. Temp hit ~200 degrees when the alarm went off. I changed both the top and bottom 1/2 of the pump so its all new with OEM parts. Most of the time it was in the perfect 140° - 145° range. Please login below or register an account with Minnesota Classic Glastron Forum. 89 Mercruiser 3. while I proceeded into the Re: Mercruiser 6. 0 models often face overheating due to clogged water pumps and faulty impellers. Mercruiser 260hp 5. 7 Mercruiser sterndrive raw water cooled. Stays nice and cool (150-160f) everywhere from 1400 to 4800 RPM. 3 mercruiser. Re: Overheat at Idle OnlyReplacing ImpellerParts and Procedure Advice? New impeller and pump rebuild kit solved my temperature problem. 9) I have removed the inlet hose to the thermostat housing, and started the motor and I have good water pressure there. Oct 29, 2022 · We were setting crab pots and idling, when the temp jumped way up and pegged the gauge. not bad, I never let it climb too high, I would put the engine into neutral & rasie the idle, the temp would fall. Dennis Allen of Affordable Marine Service explains Mercruiser Overheating Problem Solved. Mercruiser says 1-2psi at idle and 16psi or more on plane. 0 mpi overheats at idle How long has it been in the water? Obviously, you have a new engine from the original 1990 engine, did the exhaust manifolds and risers get replaced with the new engine? I would suggest you get one of those IR Temp guns and verify the engine temp to see if it actually is overheating or not. Here is how we fixed it, and how you can prevent it. 0L MPI engine. I also noticed that the idle was a little slow so I adjusted the carb so the rpm was between 800-900. It is reliable and usually the annual maintenance performed during winter layup will prevent overheating problems. It has an over heat problem. Listen to and watch this short clip on how we traced a very RARE over heating problem where engine Overheating at idle in a Mercruiser 260hp 5. mostly from a blower hose that was on one of the exhaust downpipes. If it is the manifold/riser, you'll be having hot water being forced back (stopped up) and this will start to overheat the manifold faster than the engine block (most likely). 3 Mercruiser operating temps? Overheating? Still having some overheating issues and I am completely stumped at this point so if anyone has any advice I would really appreciate it. If I push the However, it really starts to overheat after I pull it down to idle from this full throttle. Re: Mercruiser 350 MAG MPI SKI Inboard Direct Drive Overheating at Idle the thermostat slows down the water passing thru a motor to allow it to pick up heat from the engine. Overheating was experienced at low rpm but rev Author Topic: mercruiser overheat trouble shooting (Read 12474 times) 0 Members and 1 Guest are viewing this topic. I probed the actual temperature gauge sender unit at 145° whilst at the same time the temperature gauge was reading 240°. What are the common problems with 3. If I remove the thermostat it runs 130 degrees and eventually climbs to 140 to 150 after hard running. This is called a High Speed Overheat. Inspect the impeller for wear or damage, as it pumps cooling water through the engine. 3 Mercruiser Overheating The impeller is the FIRST thing to be checked in any marine overheat condition. I am out of ideas 1990 Baja 250 ES 7. Temp is steady at 160 during cruise. Re: 87 Mercruiser 4. It’s overheating when I come off plane. 7 efi merc) shut it down, let it cool and limped back in. A common issue at idle is that the old bits of the old impeller are stuck in the system and blocking low pressure water. We did some wakboarding, cruising and then we anchored at the bay. 0 Overheating at Idle: Causes and Fixes 260hp 5. Overtemps quickly when idling down after running at cruise speeds. Only registered members are allowed to access this section. I've got a Twin Mercruisr 5l Petrol (Gas) V8 set up, One of which is overheating, risers getting very hot, very quickly. Finally solved the overheating in the 5. Well here it is a new season and we went out 2 times without any issues. So now we replaced the thermostat and out drive impeller, took the boat out and still overheating at low trolling speed it Re: 4. Popped the thermostat out and it appeared to be stuck. 0L Alpha 1 Gen 1, overheat at idle, fine at higher rpm toneybrown Mar 31, 2018 1 2 Next T Just bought 1994 boat with a 4. Jan 1, 2000 · Over the years I've followed closely threads on chasing down overheating issues on this motor (circa 1985 Merc 260). When I do that water runs out at that point at low rpms and motor gets hot. 3L overheating at at idle Thank you for your input I have also thought of the impeller to be a possible source, but from all the postings I have read, it appeared that in most symptoms, the temp increased with engine speed and would cool back down at idle when the impeller was suspected of being damaged or defective. So we let her cool off an$ just fishe$ with the trolling motor till around noon. It can be a temporary problem such as weed or debris wrapped around your lower unit. Got a tow back and loaded back on trailer. 7 vortec long block. We sucked up some Sargassum weed in the Bahamas. It can also be from a more serious reason such as a bad water pump or clogged exhaust . 5psi at idle and won’t got higher then 8. 5-10 on plane. Greetings, Members! There are several posts regarding this topic, but wanted to do a refresh and ask for everyone’s help – I am at a loss at the moment. When I slow down to idle speed the starboard engine temp creeps over 200. Overheating at idle in a Mercruiser 260hp 5. each time I would come off of plane & idle into my marina, my port engine would start to overheat. It can also be from a more serious reason such as a bad water pump or clogged exhaust Re: mercruiser 5. 7 Mercruiser with Alpha 1 outdrive. Re: 87 Mercruiser overheating at idle (under 1000rpm) OK, I back flushed and then ran the boat with the muffs on and the supply hose off - dumping into the bilge. Re: mercruiser 228, 305 keep overheating any ideas!!! Another check is to pull the outdrive and put the hose garden at a medium flow to the inlet hose of bell housing and notice the temp differences. Ordered new Re: 5. Too many things can damage the impeller. Starboard engine is overheating at idle speed. Mercruiser 5. Got an 89 Searay 5. 7 overheating at idle i would post pics of the plumbing. Turns out the plastic collar in the outdrive that connects the water suction from the raw water pump to the outdrive was partially melted and restricting flow. Rev engine to 1,000 or more - engine rapidly cools to 145 degrees. May 2, 2004 · But when at idle or at low "no wake" cruising speeds the boat starts to overheat. But when things do go wrong with the cooling system, the Mercruiser is easy to troubleshoot and repair. 3l Mercruisers. 1 and got the exhaust overheat alarm each time. I am a backyard mechanic and am confident that the water impeller was installed correctly. 3L Mercruiser MPI mercruiser 4. I have a 1994 stingray 719zp that originally came with the 4. Everything is new, water circ pump, impeller in stern drive, intake manifold, exhaust manifolds, risers, thermostat housing with 140f thermostat, sensors in Hey there! I've got a 2004 Tahoe Q4 with a mercruiser 4. Re: 4. after checking the engine compartment I noticed water dripping from manifolds--both are cracked, but just dripping a little. We had to be pulled to the dock. The low water pressure is causing overheating. I did this, but problem is still there. 7 Mercruiser on my 89 Sea Ray. If the manifolds and risers were plugged up, I wouldn't expect a low pressure problem. Re: Mercruiser 4. 0 MerCruiser engines? Some common problems with 3. I had an issue that stumped me for three years (my boating season is limited to a few weeks per year on vacation), and I finally solved it and thought some might be interested. 3 mercruiser, 1 st time out it started to overheat at full throttle and also at idle, but at cruising speed 25 mph it was fine. 2L Overheating even at idle My engine over heats at idle and was told that one of my water jackets in my block was sealed shut from a previous owner that patched the block. Engine Highspeed Overheat Troubleshooting If your engine temp is OK at idle and slow speeds but when you get on plane you notice that the temp slowely keeps creeping up and up, you might have clogged and/or rusted exhaust manifold or riser water passages. I had issues on the water about a month ago overheating at idle speed. Things I have done so far: Changed the raw water pump (housing as well), changed the thermostat, replaced manifolds and risers (for another issue), drilled open the holes in the intake screen, found and fixed a few antifreeze leaks. Another common problem is the check valves/balls in the hoses - thats if thats the system you have. 0 MerCruiser engines may include overheating, corrosion, oil leaks, electrical issues, and issues with the carburetor. I replaced the thermostat and cleaned the plastic balls and I had it running perfectly for an hour in the marina between idle and 1500 rpm and the probe never gave me more than 150°. Most of these issues can be avoided or mitigated through regular maintenance, inspections, and part replacements when necessary. Cools when running. 3l mpi overheating overheating at idle Jump to Latest 9. 7 260 they are right at the entry to the y shaped exhaust collector. Under power engine temp is normal only at idle does it get hot, is this 1989 5. I had this issue with my 91 mercruiser I/O last year. The 3rd time out last Saturday set all our gear out and soon after the engine started overheating. Your engine can overheat for a variety of reasons. Couple of hours later, when we want to return to the dock, the engine starts overheating at idle. If it overheats at idle, but is better at a higher speed, it almost always points to a water flow/pressure problem. 0 often stems from a failing impeller or restricted water flow. First clue was that the impeller need to be changed so I order one and I installed yesterday, bad luck, it stills overheating. Smoke was in the engine compartment. And once i get it warmed up it overheats at idle. Engine overheats at dead idle 600 rpm. The flow seemed a little weak but when I increased the rpm it increased. Having a really annoying overheating issue. My kit had a new housing so did a complete replacement. uhrfw, 7sat, peufkx, dmk0, 0njxdn, 69ulnz, 1kt92k, 2dm3, v6t5, wh3bq,