overheat in gear

[benandbobbi]

1987 WellCraft 200 classic
fresh rebuilt 470 (I-4cyl)
new SEI 106 outdrive

1st outing - engine issues (bad carb)

2nd outing - engine overheating, initially idled at dock for 30 minutes fine, almost blew hose off water pump while on the river. Got it home, fixed the hoses, pressure checked the system, ran in yard - all fine.

3rd outing - (just got back from actually, backed into water, still on the trailer) engine idled fine for 30 minutes. I put it in gear - before i looked back, the temp rose from 185/190 to 210/215. went back, shifterd out of gear, within a minute, it cooled back off to 190. Gave it a few minutes, shifted back into gear, counted to 30 (28 actually), back up to 210. Shifted back into neutral, (engine stalls when i do this too in case that might matter), restarted and idled, temp back to 190. tried this one more time, and same results.

the engine barely seems to "bog down" when put in gear. In the water or on the hose, the outdrive rattles, almost sound like some gears are just barely touching. No problems shifting gears, other than stalling out ( i need to figure that out too).

i will drain some gear oil and see if it shows anything.

someone please help! still waiting on our 1st happy day!

[Bt Doctur]

overheat

Sounds like a damaged impeller, good on a hose because your forcing the water in.

[benandbobbi]

thanks for the reply.

the last trip, i was on the ramp backed into the river, so no hose connected.

also wanted to clarify, my idle is set 1500rpm. I installed an aftermarket temp gauge, and verified temp at sensor by infrared temp gun.

[ViperSpec]

Sounds about right. When the pump is the only thing supplying pressure (Such as, in the lake) you are having your over heat. Typically a sign of the impeller in the outdrive having failed. When on the hose, there is pressure just from the hose so that helps make up for the pumps failure in being able to move enough water. Chances are, the hub is slipping on the impeller. pretty simple fix to replace it.

[admin]

Anytime you have a high temp issue, the impeller is the most likely suspect, So I would inspect it just to make sure. It is a little odd that it is working for 30 minutes, then when you put it in gear it has a problem. You also mention that the outdrive sounds funny. I am not sure what you are hearing, but are you sure you have the drive trimmed down when you are running it. If the drive was up, the u-joints would be making all kinds of noise, and I suspect it would run fine temp wise in neutral, but once you put it in gear, the water pick up would be to high and probably be sucking air since the prop is now moving water.

Also, the idle being set at 1500 doesn't make sense. I think all mercruiser engines have a spec. of 650-850 in gear, maybe even a little less.

The gears can make some noise when it is in neutral with no load, since the driveshaft may not have popped up. The driveshaft floats up and down slightly, and when a load is applied it will pop up completely. Also if you have a heavy prop, you will sometimes get a rattle in neutral, especially if the shift adjustment isn't perfect.

Tech Support

[benandbobbi]

the outdrive was deep enough in the water that i could not see the trim cylinders, except when the occasional bigger waves came near the dock, but it was idling then. (boat was still tied down to the trailer, as i was only trying to run the engine) Shifting was only FWD so i wouldn't pull the truck in with me :)

i spoke to one of the tech guys this afternoon. I was told to remove the water inlet from the heatexchanger and see if there is water pumping through at idle and again when put in gear. That will have to wait till the weekend. i know when connected to the hose, the water would spray out all around the muffs, and when i started the engine, very little was coming out of them.

the idle is set high because of my stalling problem. i think i figured out that issue is in the shifter and the switch on the cable bracket. So that is something else i need to fix. this is our first boat, so i am learning still!

the rattling noise sounds like it could be what you are describing. I do have a SS prop.

[benandbobbi]

here's the update -
backed into the river again. removed the water hose going to the heat exchanger. started the boat, water was coming out of top hose. Not hard or fast, kind of "mushrooming" out the top of the hose held straight up running in neutral. I went up, shifted in gear and water stopped coming out. Back to neutral, and water running again. Back into gear and no water.

any ideas or next thing to check.

[Bt Doctur]

water

If shifting into gear stops the flow but returns when in neutral I would check the input shaft inside the boat when in gear, if it stops turning in gear ,the coupler is bad. Only other reason is the upper gears are melted or the lower driveshaft is stripped.

[admin]

You didn't mention if you inspected the impeller? If you haven't done that yet, please do.

Tech Support

[benandbobbi]

which impeller? the one on the pump inside the case? i didn't understand you were suggesting to open the case already. If you are referring to the one on the back, i think it is fine. The outdrive runs fine, i was able to take a short stroll last time out. when still on the trailer, it trys to push the boat and truck when i put it in gear. there is definately water pushing out the back, i was making the dock pretty rough.

[admin]

The propeller is what is pushing the boat. The impeller is what pumps the water to the engine. It is the first thing to check anytime you have an overheating issue. Regardless of being new, I would check it. They can be damaged if you run without water, and also sometimes the rubber will come unbonded from the hub.

Tech Support

[benandbobbi]

gotcha! guess if i would have slowed down and thought for a minute. Guess i am the winner of the "is this guy really this dumb" award!

guess that means the lower half will be coming off this weekend .....

oh, and thank you for responding on the weekend, i wasn't expecting that!

[benandbobbi]

ok, got it apart - doesn't look too good. Looks like the housing even has some issues. Not sure if i did something wrong or what i need to do from here.








here are a few more, but they are just the links

http://i155.photobucket.com/albums/s...DSC08141-s.jpg
http://i155.photobucket.com/albums/s...DSC08144-s.jpg
http://i155.photobucket.com/albums/s...DSC08145-s.jpg
http://i155.photobucket.com/albums/s...DSC08146-s.jpg

[admin]

It must have ran without water going to it. You will need a new water pump kit. Also depending on how long it ran, you may have damaged the water pocket cover. Shine a flashlight into the upper cavity where the water pipe is and see if that looks melted. If not, then it should be okay. If it is melted, then you need to check the exhaust boots on the engine.

You can call us Monday and we can ship the parts needed to repair the drive out to you under our 3 year fault free warranty.

Alternatively if you want it going asap, you can buy a waterpump for a late 80's alpha one from your local repair shop or west marine. You would be on the hook for the cost though.

Tech Support

[Bt Doctur]

pump

Definitely a very low/ no water issue there.That damage can happen in as little as 10 seconds without water. Most people sometimes use a bucket just covering the pickup holes not thinking that the impeller is a lot higher and it dosent really suck water but moves it. A quick impeller test is to supply just enough water pressure to have "splash" from the cups, start the engine and 99% of the splash should disappear immediatly.Stop engine, turn up the water pressure and restart the engine.