Can you believe this??? AGAIN??? Please help..

[shockerfd]

Let me recap. I bought a 97 challenger. With less than 2 hours on the boat I lost a cylinder. Great. Don't know why. I get a re-manufactured SBT engine and carb rebuild kit and assist a certified marine mechanic with the installation. We eliminated the oil injection and do premix at 40:1 as SBT recommends. The installation went well and we tune the carb to specs on land. We get to the water for the trial run and break in. The boat runs fine as I vary the rpms up to 3/4 throttle. Everything sounds good and is smooth. After about 10-15mins the boat suddenly shuts down as if someone pulled the key. Boat won't even turn over. Great. Get towed back to dock....Again! Boat turns over now but won't start. We do a comp test. Well, the same back cylinder...AGAIN on the new engine has 50 psi. WTF? Plugs looked good so we know it wasn't running lean. I'm having a hard time believing that this is just a coincidence with the new engine. Maybe, maybe not. I do have a warranty on this engine but I'm afraid the same thing could happen. But what else could possibly gone wrong??? Please help. Thanks!

 

[robin savell lloyd]

The only thing I can think of is that the back cylinder is runing hoter. than the front cylinder. This is not realy a very good answer though. You should be able to send it back and they will be able to tell you what hapened as they do not want to keep giving you free engines. :cheers:

 

[shockerfd]

Wow. No one else has a thought, opinion?

 

[JPX]

A lot of variables going on here with a full engine replacement.

I'd be worried you hit an overheating condition that made the motor shut down. Then it loosened up after cooling down - but possibly causing some minor engine damage.....hence a loss of compression.

The cooling system has to be carefully checked to make sure you don't have a dead loop of water. Hoses and fittings - and also gaskets between the exhaust pipe sections - should be inspected.

 

[shockerfd]

A lot of variables going on here with a full engine replacement.

I'd be worried you hit an overheating condition that made the motor shut down. Then it loosened up after cooling down - but possibly causing some minor engine damage.....hence a loss of compression.

The cooling system has to be carefully checked to make sure you don't have a dead loop of water. Hoses and fittings - and also gaskets between the exhaust pipe sections - should be inspected.

Thanks for the reply. You hit the nail on the head as far as what I was thinking. I've been reading up on the cooling system and all seems to be working as it says. I use the word "seems" loosely, for I can't say I'm 100% sure. Nothing "seems" obviously wrong but we all know how that can go. Any helpful hints to point me in the direction of checking the cooling system?

 

[robin savell lloyd]

If it is any help at all my engine did not go over 125* today pulling the teen's for a couple of hours with out side temp in the 80's. I had incorperated a temp guage on my boat so that I would know how hot it runs. It does not work well in the winter months as the temp guage starts at 100* and I do not see it register when It is cold out side in the winter. It is hard to believe these engines run this cold. I have read that the engines with the rave valves run hoter so you may see a bigger differance. There are other ways to see if a cylinder is runing hot and some are cheaper and easier than installing a temp guage. :cheers:

 

[shockerfd]

Well, not 100% sure the temp sensor is working but will know before "another" new engine is installed. We're going to go through the cooling system to see if anything looks suspicious. SBT said they would pull engine apart to see what went wrong and send an analysis with the new engine. It wasn't a painstaking task but not looking forward to swapping engines again. One thing I can say is that I'm getting first-hand experience with this engine....quickly!!!

 

[DiveMode]

Just a thought... did you hear any beep codes? You should've heard the long continual overheat beep before engine shut down. Heat temp sensor & wires ok? And... sorry for the troubles. That really bites. Hope it gets fixed, rather see you out on the water than on shore!! :ack:

 

[shockerfd]

Just a thought... did you hear any beep codes? You should've heard the long continual overheat beep before engine shut down. Heat temp sensor & wires ok? And... sorry for the troubles. That really bites. Hope it gets fixed, rather see you out on the water than on shore!! :ack:

No beeps at all. So, that either rules out overheating or the sensor is not working, but will find out. I don't put a lot of faith in that little sticker they stick on the heads to let you know if it did or not. But it did not change color. Yeah, having some troubles. I haven't burned a half tank of fuel yet but have lost two engines. :cuss: