Indmar 340 cat

[cigars n scotch]

For all those that have the cat 340 engine, I just talked with Larry at Indmar about a engine temp problem I have been experiencing. Occasionally at idle my temp would spike up to 170, 180 and this past weekend 203 setting an engine fault code. I check my screens Water filter, and trans cooler all were clear. check my impeller previous and was fine , but decided to replace it ...the one i pulled out looked brand new but replaced anyways...(took 30 mins on my v drive silicone lube and large needle nose vise gips and back panel remover for easier access.
Anyways Larry explained that at lower rpm with the cat running so hot that the water vapourizes to steam in the jacket and enters the top of the water distribution and then the J tube gets sucked shut from the water pump sucking causing a popping sound of the tube compressing and expanding. Giving a little throttle in gear or neutral will increase impeller flow to cool the cat and stop steam.......an fyi for cat owners and thanks for the explanation Larry

I had the same problem except I had a bad thermostat that had to be replaced. I do notice that at idle the motor runs a little hotter than normal but as soon as you put it in gear and get some water flowing it is fine. Scary experience nonetheless.

[tre]

Wow. Now there is a workaround but this is scary. As far as I know 200 is the temp where head gaskets start blowing. This is clearly a design flaw and I hope they come up with a fix and issue a recall. Who ever heard of a boat where you can't idle after the engine is hot. I have yet to see this issue in 30 hours and hopefully will not. Scary.

[roosevelt123]

I hope there is not a defect with the 340 I am on my second engine on a new 09 22ssv. first engine bent several pushrods at 30 hrs but never ran hot. Indmar made me wait 5 weeks for a new engine and ended up putting a new 2011 in the boat. wouldn't say why they made me wait for the new production run. wish me luck

[rkmfl]

Does anyone have an update on whether Indmar has come out with anything that can be done, to fix this issue, rather than requiring the workaround?

I only ask because we blew one engine while my wife was driving (damn pine needles clogged the impeller -- by the time she realized the temp was rising, she turned it off and it was too late) -- now the wife is very weary of driving the boat. We just replaced that boat (a Moomba) with our new Supra, which has the 340 CAT, and I'm worried that the wife is going to have another tramatic experience if I don't address this prior

Thank you in advance!

[kjkimball]

I have 2 boats with the 340 cat engine in them. One 2010 in Saetta Classic with 78 hrs on it, one 2011 in a Supra launch 242 with 182 hrs on it. Never had this problem with either engine. A friend with the same engine had a similar overheat at low speed which turned out to be an impeller that needed replacement which fixed the problem. I did update my 2010 engine (2011 engine has it from new) with a modification to the thermostat housing suggested by Indmar to prevent steam build up and lack of water flow in the cat manifolds. I learned of this in December when I was at Indmar for engine training but I do think info on this mod is available to dealers as well.

[docdrs]

Since this post I have had the new thermostat housing (a small hole drilled thu it) and brass fittings rather than plastic placed on the top cat cooling supply fittings.

[rkmfl]

a modification to the thermostat housing suggested by Indmar to prevent steam build up and lack of water flow in the cat manifolds.

Kjkimball & Docdrs - thanks a lot for this!

Is this something I can retrofit by removing the assembly and drilling a hole somewhere, or do I need to buy a new pump assembly? If the only option is the new pump assembly, would you go thrugh SC or Indmar?

Thanks again for your insight!
-RKM

[kjkimball]

It is a mod to the thermostat housing not the pump. It is a simple thing to do and Indmar has the data. I you decide to do it, you will need the info from Indmar, thermostat gasket, sealer, and get a thermostat and change it while you are there. Te easier way would be for you to contact Indmar service with your engine serial number and get the proper parts from them. Ask for the price on a new modified housing too and that may be low enough for yto just buy it and swap yours out instead of drilling the old one.

As I wrote before, i have one that was this way from the factory and one a year older that was not. Never had a problem with the older one but upgraded it with new parts anyway.

[docdrs]

It is a mod to the thermostat housing not the pump. It is a simple thing to do and Indmar has the data. I you decide to do it, you will need the info from Indmar, thermostat gasket, sealer, and get a thermostat and change it while you are there. Te easier way would be for you to contact Indmar service with your engine serial number and get the proper parts from them. Ask for the price on a new modified housing too and that may be low enough for yto just buy it and swap yours out instead of drilling the old one.

As I wrote before, i have one that was this way from the factory and one a year older that was not. Never had a problem with the older one but upgraded it with new parts anyway.

I agree with above. You have to remove intake cover 6 allen bolts slightly to get at tstat housing bolts unless you have universal joint shallow sockets. Its a simple 20 min job. I should have taken a pic last time I had mine off

[rkmfl]

I can't thank you guys enough for the heads-up as well as the assist on this.

I'm calling Indmar first thing tomorrow and ordering the parts/instructions.

Once I get them I'll scan/post here, for others.

Thanks again,
-RKM