engine overheat
 

Hello guys I need your help on this one

I have a ford gt-40 engine in my boat. Today was the first time of the season my boat went at the lake. Just before I changed the raw water pump with a brand new one because the bearing on the old one were destroyed. My boat started fine but soon after there was a rubber burning sent and smoke I'm pretty sure It was coming from the strap being too loose. Just as I turn off the boat I noticed the engine temp was higher than usually about 200 F. So I let the engine cool down and after I restarted it and looked at the raw water pump pulley and it was turning and the strap doesn't seem to slip...but soon after the engine overheated again....

Does someone have an idea of what is my problem?

I am pretty sure I mounted the pump in the right direction but how can I be sure?

Maybe the overheating come from the slipping strap but the second time I started the boat it looked like the strap was not slipping too much....

Can I have a problem with the water filter just before the pump? is it possible that water left in the filter in the winter broke it? (it was the only part not winterized correctly...

Thanks for your help guys no good inboard mechnaic in my area so I have to find the problem by myself...

Replace the belt/belts and correctly tighten it/them, then run it off a fake-a-lake and re-check engine operating temp and check to be sure you are getting decent water flow coming out the exhaust. If you replace the entire raw water pump, there is no way you could have anything backwards. Now if you just replaced the impeller, that'd be a different story...

...And if it is a serpentine type belt, make sure you have it routed correctly, but I doubt you could get it tight if you had it routed wrong.

he doesn't say where he is from it was a cold winter.if it wasn't winterized properly who knows.can you pull on the fins on your alternator and spin them?

Make sure all of your hose clamps are tight from when you replaced the pump. If they are loose it will suck air and cause it to run hot.

Not real familiar with that engine. I would suggest thermostat, mine overheated last summer and it was stuck closed. Got the new one and it worked fine, this year it was stuck open, go figure. Easy fix for about $13 if that's the case.

Was your old impeller get destroyed when you changed it? When impellers go out the pieces that break off will get circulated into the engine. They can clog water hoses and plug up thermostats. If not all the pieces are accounted for I would recommend that you back flush all your hoses, remove the thermostat and see if any pieces went in there. I would just replace the thermostat if you are opening it up. Do that and you should be fine.

Also make sure when you replaced your pump its going the right way. It only sucks water one way. That might be your problem. Easy way to check it. Remove the hose going to the engine from the water pump. (the top hose) Start the boat and give it gas. The water should spray out the hose. If it doesn't have a bunch of pressure, the pump it probably backwards. Oh! make sure you only do this for a few seconds, and rehook the hose right after you are done! :)

I agree with Kyle, most likely casue (if you had the pump off) is that either the impellar was installed incorrectly with the fins going the wrong way, or the Raw Water Pump was installed up side down. If you havent had the pump off, you impellar is probably toast and needs to be replaced.

To chec kyour orientation of the Raw Water pump: pull the top hose coming from the Raw Water Pump off at the Tstat housing, fill it with water from a cup and then turn the motor over. If the pump is correctly orientated, the water will shoot out of the hose, if its backwards it will suck the water into the pump.

Also, you can visually look at the side of the pump housing. if it is oriented correctly, there is a set screw (not a mounting screw) on the side closest to the engine. If that set screw is to the outside of the pump (away from the motor) it is on up side down.

The fins will straighten out by them selves. The housing is not perfectly round leaving room for them to go what direction they need. You can put the impeller in one way and turn it by hand the other way and watch the fins switch directions. Yes I have done this to see after reading it on this forum a few years ago.

My guess would be that thte hoses were installed backwards when the pump was installed, and that the smoke came from the new impeller burning up. Take the pump off and disassemble it and inspect it for damage.

Aaron, sometimes they flip over if installed backwards, sometimes they rip apart.

Check the inpeller

Thanks so much for all that are trying to help me!

I tried some things tonight before I saw your suggestion

I disasembled the pump and found that it was completly dry no water the impeler looked fine a little bit of rubber dust in the pump but nothing broken..

I did put a water hose in the boat inlet to see if water was coming from boat inlet to water pump that was fine

So I thought maybe the pump need to be primed to be able to suck water to the engine so I put back the pump and bottom hose and filled it with water from the top and put back the hose. I started the engine and ran the boat slowly for some time the temperature stayed very low almost no movement to the gauge. So I tought my problem was solved the pump just needed to be primed. So I opened the throttle at about 3/4 and immediatly smoke began to come from the engine (rubber burn sent) and the temperature gauge went to 200 F .So I closed the throttle to idle but the engine temperature doesn't drop...

It looks like the strap is maybe slipping when engine rpm goes higher...so the pump stop or turn slowly but the pump is supposed to pump water again at idle speed and then cool down the engine?

After I stopped the engine and I touched the strap and it was not hot...but the pump was really hot....


Chris, if your talking about the screw that goes in the cam (so the cam screw) my pump is not on the right position...my screw is not on the engine side...
http://www.pumpagents.com/pdf/SherwoodPumps/G21.pdf

So if you are right my impeller flipped..... but the pump look symetric do you guys think that once the impeller is flipped it should suck water no matter how the pump is mounted ( if it's symmetric)..

Does someone know the model number of the pump strap? my boat is a 97 hydrodyne with efi PCM 351 gt-40 pro boss engine

Thanks so much!

When you say the "strap" are you refering to the belt? When the boat is at idle with the water hose hooked up. Do you have water coming out the exhaust ports?

Yes I mean Belt sorry for my poor english

I tried but the exhaust were half in the water but I am pretty sure there was water going to the engine since the gauge was reading very low as soon as I opened the throttle a lot smoke came from engine and temperature quickly raised...

I'm betting your pump is upside down. Yes I was talking about the Cam Screw. Pull the top hose off and fill it with water like I said above and see if it sucks it in or pumps it out to confirm that it is for a fact.. If it does suck water instead of pushing it, rotate the entire pump 180 degrees. The Raw Water Pump works off of a vacume and will only pump water in one direction. If you are seeing "rubber dust" you probably need to replace the impellar as well. It does not like to be ran dry.

Your belt should be snug but not overly tight. When you push down on the belt with your finger it should have about a 1/4 inch of give to it. (about 6 mm). It should not slip at any RPM, any tighter and you will wear the bearing in the pump arm out though.

to replace your belt, skidim has them as a set for $15. or just take yours off and go down to any autoparts store and get them to match it.

Thank you so much Chris,

Does someone have a belt number for my engine....I lost the belt in the dark yesterday.....

Thanks

9 times out of 10 this will be the pump installed backwards. a real easy check is to take the hose off going to the engine (most likely thermostat if i remember correctly) after the pump and see if it is pumping water. if it is not spiting water the pump is in backwards... take off the entire pump assembly and turn it around and repeat the visual test with the hose from the pump. If it is still not pumping water you have other issues.

I dont know the part number, but if you dont have one yet, call Skidim or any dealership. They can give you the PN or sell you a replacement.

Sorry, scratch calling (im assuming your not in the US?) email Richard at Skidim salesskidim@sc.rr.com he can get you what you need.