indmar engine gurus

[gcombe74]

helping a friend out.. 99 supra. indmar 350. have replaced thermostat, but on a fake a lake wont draw water up past the first water pump.(impellar looks to be in good shape as well) seems that the engine is back preasuring and not allowing water into the motor? pretty much checked all hoses and passage ways and none are blocked.

drove to the lake... make sure had enough water and the engine temp just rose up more and more.

is it possible bad head gasket or cracked block is causing this? he just tried to take it out 2 days ago for the first time since last winter... was stored in a storage shed but not heated.

[mmandley]

Using a fake a lake you can check everything out.

Remove the thermostate and hook the fake a lake up, turn on the water start the boat for a minute
Water shoots out the T state then engine is flowing water
No Water? Blockage is in the engine possible head gasket but i doubt it would stop all water. Then you would have hydro lock of the engine, or the water pump its self.
You could have a bad water pump as well, i would expect it wouldnt turn and you would burn off the belt. Still a possiblity.

Water at the T state
Recconect the T state piping but leave out the T state for now.
Start the engine with the fake a lake.
Water out the rear? Yes then your T state its self was bad
No? Then shut it down
Now remove the muffler from the Exhaust manifolds
Start it up with the Fake A Lake
Water Yes? Muffler is prolly bad
No? Then your Exhaust manifolds are the issue.

This should get you most of the way through it.

I am no Idmar guru, but im an engine motorhead.

[kaneboats]

Be sure you are familiar with post #1 here:

https://forum.moomba.com/showthread.php?22169-Great-Tips-of-the-week-month

[gcombe74]

Using a fake a lake you can check everything out.

Remove the thermostate and hook the fake a lake up, turn on the water start the boat for a minute
Water shoots out the T state then engine is flowing water
No Water? Blockage is in the engine possible head gasket but i doubt it would stop all water. Then you would have hydro lock of the engine, or the water pump its self.
You could have a bad water pump as well, i would expect it wouldnt turn and you would burn off the belt. Still a possiblity.

Water at the T state
Recconect the T state piping but leave out the T state for now.
Start the engine with the fake a lake.
Water out the rear? Yes then your T state its self was bad
No? Then shut it down
Now remove the muffler from the Exhaust manifolds
Start it up with the Fake A Lake
Water Yes? Muffler is prolly bad
No? Then your Exhaust manifolds are the issue.

This should get you most of the way through it.

I am no Idmar guru, but im an engine motorhead.

I removed the water pump.. it rotates freely. and put it all back together before I posted.

I also took my hose and directly put in in the hose that goes into the water pump \ T state.. but it actually back preasured and water was being forced back out where i was putting it in.. which has let me to believe that 1. I have a head gasket issue... that is back presuring the water side. while doing this I had the hose off the end that dump in the exhuast manifold.. and very little water was flowing form it.. but i believe that is because the preasure is part of the issue.. you would think water being forced in that way would be forced in.. but the engine is presuring back the way it came.. not allowing to flow in.

I suppose I can remove the thermostate and test again with that out. but like I said I replaced it.. and also blew throw that T state setup and no blockage?

[mmandley]

I removed the water pump.. it rotates freely. and put it all back together before I posted.

I also took my hose and directly put in in the hose that goes into the water pump \ T state.. but it actually back preasured and water was being forced back out where i was putting it in.. which has let me to believe that 1. I have a head gasket issue... that is back presuring the water side. while doing this I had the hose off the end that dump in the exhuast manifold.. and very little water was flowing form it.. but i believe that is because the preasure is part of the issue.. you would think water being forced in that way would be forced in.. but the engine is presuring back the way it came.. not allowing to flow in.

I suppose I can remove the thermostate and test again with that out. but like I said I replaced it.. and also blew throw that T state setup and no blockage?

I understand but the engine is full of very small passages for the water, and the water pump pumps it through at very high pressure, close to 4 gallons a minute, so using a garden hose that is 1 inch in diameter to push water through a 1/4 inch at best hole is going to create a natural back pressure and give you false readings.

You really need the pressure of the water pump to see if there is a blockage in the engine.

Also you cant test water flow through an engine with the T stat installed because it required the engine to heat up to 140 before it will even start to open, so at this point you will get No water flow, and from the time it hits 140 to 220 over heating is only a minute or 2 at best.

This is why testing without the T state is important, because all you need to see is if you have water flow.

Also is your buddy the same owner of the Supra as last summer? Or did he just pick this boat up?
If he is the owner did he over heat it last summer?
If so i would replace the Impeller first, and then continue with the above TSS.
If he is a new owner of the boat then i would continue to TSS.

Normally even if you blow a head gasket it wont Stop all water flow through an engine because its not 1 path all the way through. It has 1 main inlet then braches through the heads, block and such. Other wise you would always have 1 side of the engine running hotter then the other.

[Rossterman]

Does it have a transmission cooler downstream of the pump? Could be blocked by leaves or trash. Also some folks have put in the wrong impeller- there is a 2" and a 1 7/8" . When using the shorter one. The pump usually loses suction and overheats over idle.

[gcombe74]

I understand but the engine is full of very small passages for the water, and the water pump pumps it through at very high pressure, close to 4 gallons a minute, so using a garden hose that is 1 inch in diameter to push water through a 1/4 inch at best hole is going to create a natural back pressure and give you false readings.

You really need the pressure of the water pump to see if there is a blockage in the engine.

Also you cant test water flow through an engine with the T stat installed because it required the engine to heat up to 140 before it will even start to open, so at this point you will get No water flow, and from the time it hits 140 to 220 over heating is only a minute or 2 at best.

This is why testing without the T state is important, because all you need to see is if you have water flow.

Also is your buddy the same owner of the Supra as last summer? Or did he just pick this boat up?
If he is the owner did he over heat it last summer?
If so i would replace the Impeller first, and then continue with the above TSS.
If he is a new owner of the boat then i would continue to TSS.

Normally even if you blow a head gasket it wont Stop all water flow through an engine because its not 1 path all the way through. It has 1 main inlet then braches through the heads, block and such. Other wise you would always have 1 side of the engine running hotter then the other.


same boat.. different issue... last summer his issue was vapor lock....

I have a new impeller... so I can throw that in as well.. but the old one is fine. I will see what i can do to route around the T stat.... I compression tested the heads as well... for the year \ make \ model it seems to be fine... 155 the high end... 150 the low.. so nothing glaring.. I would think higher overall, but given none are way out of the rest seems to be ok. has to be blockage of the whole system. because as you state... there are multiple paths.

[gcombe74]

same boat.. different issue... last summer his issue was vapor lock....

I have a new impeller... so I can throw that in as well.. but the old one is fine. I will see what i can do to route around the T stat.... I compression tested the heads as well... for the year \ make \ model it seems to be fine... 155 the high end... 150 the low.. so nothing glaring.. I would think higher overall, but given none are way out of the rest seems to be ok. has to be blockage of the whole system. because as you state... there are multiple paths.



still no go. brand new impellar. will not flow water past this point in the motor no matter what i do.. removed thermostat as well.
but wont go past impellar to the Tstat.

[maxpower220]

So, have you tested the engine water pump? I understand that your raw water pump is fine. It gets water up to the engine. The engine water pump circulates water in the engine. Also, have you removed the exhaust riser to check it?

Those are the 2 things I would check for your issue. Even if there is a blockage in the engine block/head, it would only affect one bank and the other would flow.

[gcombe74]

So, have you tested the engine water pump? I understand that your raw water pump is fine. It gets water up to the engine. The engine water pump circulates water in the engine. Also, have you removed the exhaust riser to check it?

Those are the 2 things I would check for your issue. Even if there is a blockage in the engine block/head, it would only affect one bank and the other would flow.


water does not even make it that far. pretty much wont pass water past the first pump. I did pull off the T stat. removed circulation pump... seemed fine. freely moves and not the seal seemed good.

I removed the exhaust head.. as well. no blockage. I am giong with blown head gasket here... makes perfect sense at this point. had this happen to my 99 alero... would force all the coolant out of the radiator to the over flow tank and to the ground.... in this case it just forces water back down the intake hose.

[parrothd]

What happens when the engine is off and water on?

Sent from my Nexus 4 using Tapatalk 2

[gcombe74]

What happens when the engine is off and water on?

Sent from my Nexus 4 using Tapatalk 2


water flows as far as it can into the water pump....

[gcombe74]

mystery solved... the boat came to me with the water hoses switched at the water pump. just over looked that given the boat was just at the only moomba \ supra dealer in SLC. :confused: just did not look or think something that basic would be the case.... switched and works perfect.

[Stazi]

How the f#$k did they manage that, and why was it like that?

[94Boom]

How the f#$k did they manage that, and why was it like that?

Well I can only speak for myself here but I am on my third impeller on my Boomerang and it was totally self inflicted. Took it out of the boat in the spring, forgot to mark in and out so took an educated guess at how it went in. Went to the lake, fired up the motor with the boat backed in the water and the water pump started to smoke. I put in another one the same way because I thought I didn't have it backed in the water enough. Smoked that one as well. Flipped the pump around, presto lots of water. Guess I need more education because my educated guess was wrong, but I know now.

Brian

[gcombe74]

How the f#$k did they manage that, and why was it like that?


well was taken to MP for them to summerize... had not been used since last winter... the guys that own this boat have friends and connections with boats and have been off living the good life riding on some other peoples dime and time..(lucky them)... so when the got around to using it.. it just started to over heat.... when MP had it they replaced the serpentine belt and must have switched the hoses at that point.... go figure.

I just assumed it was right... guess we know what assume gets you.