problems after weed sucking

[cykrus]

Hello Guys,

First of all I have a challenger 1996 that has an engine 1503 4tec, 155hp. The engined comes from a PWC the guy did a great job adapting it (pictures in a different post).

2 weeks ago, I took my boat on a lake where ... i did not realize there was a lot of weed. I went full speed into it, the engine sucked it and lost speed. I tried accelerating slow a few times no luck and then i got the HI-TEMP . Stopped the engine right away .. let it cool tried again, i git again the HI-TEMP. Stopped and lucky me I paddled to the shore. There I went in the water and using a knife i cut all the weed from the grate. Started the engine ... worked ok but something happened aver since. When I accelerate, before I get on plane mode the engines makes a strange (broken) sound .. as a car does when the exhaust is cracked. If I am alone in the boat I accelerate and I get on plane mode and everything is ok .. then full speed as before. If I have 2-3 passengers with me the boat before i reach plane mode I get the HI-TEMP warning and i have to shut it down. I cannot get on plane mode with 2-3 person on the boat. Alone or me and a passenger it still works, although the strange broken sound in the exhaust.

I have checked at home there is no weed left in the pump, I suppose there is a clog somewhere in the exhaust cooling system (the box i supposed it is called). Can someone explain me how does the water get to that box ? I looked under the boat there is no special hole so i suppose it comes somewhere from the pump ? Can it clog ?

Even If I am alone in the blat and i start it and let it idle in 5 minutes I will get the HI-TEMP. Once I get speed I can go for hours without problems.

I have also notices that on idle mode on the small hole that usually spills a jet of water, on the back of the engine cover, there instead of water is smoke. Once i get it on speed it will shoot water there but I think the jet is way less powerful than it was before.

I thought I have burned the gasket isolator ... but have checked the compression on each cylinder and i get 170-180 as it was before.

With the HI-TEMP i stopped the engine right away, within 3-4 seconds from getting the message.

Any ideas where to start from ?

Thanks
Vlad

 

[XP 787]

That smoke you are seeing is steam from residual water being burned off usually before overheating. I am pretty sure that the 4tec engines have a closed loop cooling system meaning it does not use lake water to cool the engine.

You say you get 170-180 psi on the compression test. Is this across all 3 cylinders or are you getting 170 in one cylinder and 180 in another?

 

[cykrus]

Thank for your answer. The compression was 175 one reading 180 another reading. the compression was equal on all cylinders.
You are right, it has 2 cooling systems, 1 for the engine (that is closed with antifreeze) and the other one for the water box (exhaust) that uses water lake. When I run the engine out of the water I need to connect the water hose in order to cool the water box and water comes out of the exhaust. So I am not 100% sure but i suppose the problem than i am facing is with the exhaust cooling system.

 

[cykrus]

Just did another test right now and here are the results. I have connected the water house to the boat, started the engine, turned on the water. I noticed that part of the water came out through the exhaust (that is normal to cool of the water box) but most of the water came out though the jet pump - is this ok ? Shouldn't all the water came out through the exhaust ?

The water hose goes to the engine block (#1) then though the 2" metal pipe to the box (#2) and then through 2" the rubber hose to the exhaust and out of the boat (#3). Now I ask myself ... can it be clogged something inside the water box ?

My question is because of the fact describe above ... connected the water hose .. the MOST OF the water went, in my opinion from the hose to point (#1) and then towards the water box but did not get there, as it was exiting in the rubber hose that is on the middle of the 2" METAL hose and from there to the pump. So little water got to the water box in order to cool it. Could it be that that something backwards is happening while I am in water and the water from the pump goes towards the heads of cylinders (and from there outside through the place where I have connected the water hose while ruining it out of water) and not towards the box to cool it ? ...

How much water does it need the water box in order to cool it. I used the normal garden hose with water from the municipality, at maximum

If my explication is too complicate I can add some pictures.

 

[pete63]

about 95% though pump, rest though exhaust.
either you have something slightly blocking the water passage in the pump, or exhaust manifold/ j pipe. do a seach on the forum for over heating or j pipe blockage.
the other alternative is a slight cavitation or pump blockage causing lack of power, speed and water flow though pump, which will lead to hi temp.
hi temp also can be coolant (closed loop) so check coolant level.

 

[cykrus]

thanks, that was 90 % through the pump so that is ok

J pipe, nice name i know it from now on. i took the hose from the pump to j pipe out blew it with my mouth and it clean, nothing there

cooland i have it more than max but there is an overflow hose so i dont think it's a problem

cavitation yes! lost a little bit if power yes but what causes this ? i checked the pump from under the boat and from the back and it's clean no debris in there. what could be the other csuse of cavitation? i feel a little bit of cavitation you are right before it gets to plane on water . tasnks starting to learn it

 

[kwmnh]

it comes from wear ring, most of the time. check impeller, carbon seal and boot too.

 

[Eclipse1701d]

There are three tiny holes at the bottom of the j-pipe, just before the water box connected to three veins that wrap around the outside of the j-pipe. These provide the water that cool the exhaust. They are fed by the three hoses that connect to the pipe. Open the c-clamp that connects the pipe to the engine. Remove the hoses connected to the j-pipe, and loosen the four clamps that hold the j-pipe into the water box. Remove the j-pipe. Check to see if any of the tiny holes toward the end of the j-pipe where it enters the waterbox are clogged. Use and air compressor to clean each hole. Cover two of the three holes each time to increase air flow. Remove each hose the connected to the air pipe from its origination point at the engine and use the compressor to blow out each hose. Also, check for and remove any foreign objects from inside the water box. Reverse the procedure. Good luck!

P.S. - I just realized, the title of this post is kinda funny...

 

[pete63]

best to pull the pump and check inside the pump and impeller for damage to the impeller, object stuck or grooves in the wear ring.