View Full Version : HELP! 1996 LT1...water!

07-15-2011, 02:20 PM
Just hit the lake and the bilge pump was pumping water. Lifted calon and a steady stream of water was pouring from a hole in the bottom of the manifold that's directly under air filter....help!!!!

07-15-2011, 02:39 PM
There are alot of water hoses that hook up in that location, as well as the water circulating pump which kinda looks like a manifold, directly under the flame arrestor (maybe 6-8" under the flame arrestor?). If the water circ pump bearing is failing, there will be a drip, then steady SMALL stream of water that comes directly out of the weep hole on the bottom of the water pump. More water = pump closer to failing.
If that's what you see, you ned a new water circ pump (not a raw water pump which is bolted to the crankshaft snout, below the circ pump). Otherwise, trace the leak to a bad hose or something.
If you're pulling the whole mess apart it's a good time to replace the thermostats. LT-1 has 2 Tstats a 143 deg that controls water to the exhaust manifolds and a 160deg that controls water to the engine. The 160deg has a bypass hole drilled in it. Make sure you buy the correct specific tstat for this form a dealer or Skidim, etc, or copy EXACTLY what is in the boat assuming it's correct when drilling a bypass hole in a parts store tstat.

07-15-2011, 02:51 PM
This water is coming from the weep hole in the bottom of the manifold directly under arrester

07-15-2011, 02:58 PM
Like right where the big hose and the little one with the brass 90 are in my pic?
Not sure, if it was the water pump I think the weep hole for that would be lower, under the water circ pump and not actually visible without a mirror.

07-15-2011, 03:12 PM
Can't see it unless I get contorted and lay down...

07-15-2011, 03:13 PM
Temp running 145

07-15-2011, 03:40 PM
CIRC PUMP is gone....

We have them...please call Chuck at (813) 996 2297


07-15-2011, 03:44 PM
So I guess I'm dead in water today

07-15-2011, 07:10 PM
Jim...thanks for the help. Chuck said it will be here by Wednesday so that means hopefully I'll be back up and skiing nxt Saturday. Anyone got any pointers for this changeout? I am changing the 160 tstat out at the same time since the motor temp has been stuck on 143

07-15-2011, 07:37 PM
I changed mine about two years ago, and it was a pain because I have the V-drive. IIRC I allen head sockets on some parts, I can't remember which ones, but it was pretty straight foward. Not much different than an automobile. Lots of skinned knuckles! Should only take a couple of hours.

07-15-2011, 08:09 PM
Is it normal for the Circ Pump to drip a little the first time out after the winter? I had a steady drip the first time out but have not had one since. Is this normal or just telling me it's going to fail soon?

07-15-2011, 08:20 PM
It should't drip at all. If it's original it probably needs changing .

Sent from my VS910 4G using Tapatalk

07-15-2011, 10:03 PM
Is it normal for the Circ Pump to drip a little the first time out after the winter? I had a steady drip the first time out but have not had one since. Is this normal or just telling me it's going to fail soon?

The front seal on the pump probably shrank from sitting, once it warmed up and got used the seal expanded to it's normal size, I would run it until it's starts to leak when the engine is in use then change the water pump

07-16-2011, 11:30 AM
^^^ Yes.
Change both thermostats. LT-1's are awesome, but a little more finicky and a little less forgiving (aluminum heads) if overheated.

07-16-2011, 12:46 PM
Got the it all taken apart and ready for the new parts to get here next week. My nephew and niece will be in town next weekend so I hope to be back up and running. Any tips?

07-16-2011, 01:40 PM
Might be a good time to paint the brackets, bolts, and raw water pump if they need it.

07-16-2011, 03:05 PM
don't forget to put sealant on the bolts, some of them go into the water jacket

07-16-2011, 07:20 PM
thanks 1redTA....thats the details I need to know!

07-17-2011, 01:28 PM
don't forget to put sealant on the bolts, some of them go into the water jacket

You s/b able to see which ones are corroded, those go into the water jackets.
Also, IIRC all the mounting bolts are same dia, but some are diff length. Keep track of which ones came from where.
Makse sure the mating surface is completely clean....ALL gasket material scraped,wire brushed off. I alwyas use a real thin coating of RTV sealant on both sides of the gasket no matter how good the surfaces look. Spread it real thin with your finger so hardly any oozes out when you tighten the bolts.
Check the hose ends on an older boat like that to make sure they'e not splitting or cracked. If they look sketchy order up the big hoses and replace the heater hoses while you have it apart.

07-18-2011, 09:27 AM
trying not to sound stupid but which thermostat is the 160....?

07-18-2011, 09:48 AM
Let someone else confirm 100%, but the top stat is the 160, bottom one is 143. Should be stamped on the stats you remove. Also make sure the 160 has the bypass hole drilled in it.
Copy what was in the boat if you buy an auto parts stat with no hole.

07-18-2011, 09:59 AM
10-4 Thanks...I've haven't looked that close yet, was waiting for the new pump to come in. Thanks for all the help.

07-18-2011, 12:27 PM
Had some thermostat questions myself a few years ago....


The 160 is on top (hole drilled) and the 143 is in front.

07-21-2011, 10:46 PM
ok....installed new circ pump and both new thermostats...boat runs 160 sitting in the water but rises to settle at 175 running 35 mph....

before the circ pump went out it was steady at 143....should i be concerned?

07-21-2011, 10:53 PM
Well, 175 isn't terrible, but seems weird unless your guage is off.

Presume it stayed at 160 before changing thermostats?

07-21-2011, 11:01 PM
it actually ran at 143...the 160 thermo was bad...i replaced both thermo stats....if i ran it up to 40 mph it ran around 160... at 20-30 it was running between 160-180 but not all the way to 180...sitting idle for a few minutes it ran back down to 160....but mostly running it was around 170-175

07-21-2011, 11:08 PM
One would think it would get hotter as you put more fuel to it.
Is your impeller good?
Check the screen in the trans cooler for any debris?
I wouldn't stress about it if it's not leaking, manifolds are running cool (getting water) and the boat is running fine.
My 190 wouldn't always stay pegged at 160 either. If the temp guage starts going up ck the manifolds first to see if they're getting hotter than normal (indication of not getting enough water).

07-21-2011, 11:14 PM
it never broke 180 degrees....i cleaned the screen at the end...probably going to order a new impeller and temp sensor just to be sure.

07-21-2011, 11:38 PM
i think that if i don't like how it runs this weekend I will take the 160 thermostat out and let it run off the 143...it was running great before the circ pump went out and in south Alabama our lake water is 80 degrees...like bath water....

07-22-2011, 01:44 AM
Did it not have a top tstat before?
Not a good idea to run without a thermostat. Not like old carbed engines. EFI's will enrich the fuel mixture, like a choke, when the engine is cold and will lean it back out as the engine warms up. Running a colder stat or none at all will be like running with the choke on.
The LT-1 and most other newer efi engines regulate fuel enrichment based off of coolant temps.
I haven't tired running without a thermostat, but it stands to reason, since there's no choke to provide more fuel (or less air).

07-22-2011, 08:09 AM
the top thermostat was obviously stuck or something....it was there but the motor ran at 143 all the time. Is it ok for the motor to run at 170-175 degrees on the water a mojority of the time...can I get a new temp sensor at the auto parts store or do I have to order one?...same question for impellor....?

07-22-2011, 08:16 AM
For the impellor, call or go online to skidim. For the temp sensor, most any auto parts store should have it.

07-22-2011, 08:55 AM
I just read the Indmar Manual for the boat and it said the Power Reduction Mode would kick in at 176 degrees, I don't want that to happen.....I swear, I really want to be on the water tomorrow...going to clean all the hoses out real good this afternoon and check the thermostats I just put in....replace the temp sensor....make sure no air leaks....hopefully I will be good.

07-22-2011, 11:21 AM
After talking with Chuck at BAWS I am certain that my impeller is going bad...I ordered a new one and it's on the way...impeller probably not pressuring up the system enough and the new circ pump cavitating (the old circ pump was completely gone)...makes sense to me. I appreicate all the help from Jim and Chuck at BAWS.

07-22-2011, 12:07 PM
Your lucky your circ pump came off easy. Mine wont budge =( And it leaks... temps should be 160-165

07-22-2011, 12:18 PM
the circ pump changeout went great!...it leaked something awful, cleaned out my bilge pump well...problem is I should have ordered an impeller at the same time for the other pump...I will play on it a little tomorrow and keep close eye on temp...new impeller be here next week.

07-22-2011, 12:36 PM
my pump came with a new impeller, but it doesnt help me that i cant get the old pump off haha