i over heated my motor, now what?

jimmythemufflers · **Joined:** Tue Aug 05, 2014 8:26 pm **Posts:** 40

2014 h190rs 4.3 VP fuel injected 225. So i was cruising just over 4000 rpms and i trimmed up a tad too much. My buzzer alarm went off, my temp gauge was almost all the way up so i stopped. at idle the temp gauge went down almost instantly and the buzzer went off. THE SCARY PART! There was steam coming out of the engine compartnent. I shut off the motor and fliped the blower on and opened the hatch until it stopped. I restarted and all was back to normal.

Im guessing i trimmedbtoo high and couldnt suck up any water, or some weeds may have blocked the intake... Did my alarm save me or could i have damaged something? Its running just fine but im a bit uneasy about this. Ive only got 25 hours on this boat... come on guys, make me feel better here...

LouC · **Posted:** Sat Aug 30, 2014 7:07 am

Its probably fine, keep in mind that the alarms are set to go off at about 200*. In the automotive application these engines ran at that temp normally (Chevy 4.3 V-6s came with 195* thermostats). In the marine application they use a 160* stat because its an open system, raw water and not pressurized like a vehicle. So water in the engine can start to boil at about 200. The other reason they are set to run cooler is to keep the exhaust cool. The steam you saw might have been the exhaust rubber hoses getting hot. I overheated mine last summer and I would up replacing the exhaust flappers (the Volvo does not have them in the Y pipe so don't worry) and the exhaust hoses (not burned but getting stiff and were 25 years old). Just make sure when you trim that up all the way, you are at idle. I never trim up past having the drive just a bit above being level. The reason is that turbulence at the lower unit can disturb the raw water flow.

As long as its running at normal temps I would not worry. I would advise anyone to get a Radio Shack IR Temp gun. Then take readings when everything is right. Exhaust manifolds on mine are usually 100* at idle and they hit a peak of 125-130 right after coming off plane. If they are getting hotter than that like 160 then I start looking for low raw water flow problems. Its possible to have high exhaust temps and not overheat the engine. I think every inboard should have alarms for engine temp and oil pressure but also for exhaust temp.

crossram · **Posted:** Sat Aug 30, 2014 10:50 am

you should be alright if you shut it down right when alarm went off it didnt get too hot . its possible the steam was the new paint getting baked off from fist time at that temp

jimmythemufflers · **Joined:** Tue Aug 05, 2014 8:26 pm **Posts:** 40

All good news. Thank you for the peace of mind. I got crazy with the trim. I wont be doing that anymore lol. So the gm blocks are near identical? I suppose it makes sense to compare the 2 than. Burnt Paint maybe. It was whiteish, clear just like steam. Didnt smell like anything.

I have a tool box under the hatch along with a jump box. A ir temp gun may fit n there depending on the size.

LouC · **Posted:** Sat Aug 30, 2014 12:52 pm

The reason why these engines are forgiving of overheating is that they are old school cast iron blocks/heads. Much for forgiving than aluminum. Also the cylinders are not siamesed (there is cooling space between them) and are a closed deck design. This is where inboards are better than outboards, the heavier construction will tolerate overheats better.
With trimming what I have done (since you really can't depend on the gauge much), is count how long it takes to go from full down to full up. Half of that time is 1/2 up, 1/4th is 1/4th etc. For my boat the optimum trim angle is about 1/4 up.
Also I measured how much my boat drafts with the drive all the way down (36") half up (30") and all the way up (18"). This is good to know if you have a lot of shallow spots.....
Lastly, I measured out one foot intervals on my boat hook, and marked them on it. Then I used this to get the keel offset adjustment on my Garmin right on the nose. So now when it says 6' its really 6'.....

ric · **Posted:** Sat Aug 30, 2014 4:37 pm

Make sure you didn't break the plastic pickup tube fitting in the outdrive. It will run cool at slow speeds and idling around, but will overheat at plane.

Graham R · **Posted:** Sat Aug 30, 2014 5:08 pm

I'd have thought the main point of concern was the impellor; not enough water getting to the exhaust/ engine so to cause an overheat = the impellor not getting water, running dry in it's housing and wearing/ breaking up. But my wife old me after the fiasco (debacle) with our 278 Vista and it's EVC system that I know nothing, so I may well be wrong !

LouC · **Posted:** Sat Aug 30, 2014 7:36 pm

If the engine and exhaust are at normal temps (that's why I advised taking readings with the IR temp gun) the impeller may be fine. I'm not familiar with Volvo's maintenance schedule but they may recommend yearly replacement for the impeller. In which case you could do it at the beginning of next season. I have found that as long as you don't run in shallow sandy water the impellers on the Cobra last at least 3 years. At the same time I have found that you can have one that looks fine but just doesn't pump like a new one.

Graham that is one reason why I have stuck with the stone age technology I have (breaker points, Rochester Quadrajet, dog clutch shifting). Its crude but it works and is very easily fixed. At the end of the day, 'easily fixed' is about the most important thing in the boating world......Ignition dies, well pop in a new set of breaker points. Carb acting funny, get the spare rebuilt and swap them, etc.

SeaTea · **Joined:** Sun Aug 11, 2013 6:44 pm **Posts:** 13

Sure sounds like steam if it was clear and didn't smell. You either had lots of water in your bilge and it contacted the y-pipe or a closed system became an open one. There shouldn't be any reason to have steam in your engine compartment under those circumstances.

You sure you don't have a leak somewhere? Do you have water in the bilge after running? Is the bilge pump coming on? Does it work?

The steam sounds suspicious to me.

www.iFourWinns.com

i over heated my motor, now what?

Who is online