Proper operating temps??
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=2586
Printed Date: November-26-2024 at 10:57pm
Topic: Proper operating temps??
Posted By: Guests
Subject: Proper operating temps??
Date Posted: October-11-2005 at 11:38am
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On my newly acquired 79 SN 351 I queried the PO about the operating temps as the boat appears to have a 180 degree thermostat installed.
It does not fluctuate but as I remember from the manual and the way my 302 runs (fishing boat) the raw water boats should have a 140 degree thermostat shouldn't they? This engine doesn't like to start after sitting for 15 minutes in the middle of the lake. I can start it but then is seems to be cold blooded. Was this a typical fix for these cold blooded symptoms on the older Commanders? Thanks for the input. |
Replies:
Posted By: Guests
Date Posted: October-11-2005 at 12:14pm
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One other question...
When hooking up to a hose can you put a valve inline at the raw water intake (I'm thinking a two way valve inline on the intake hose after the tranny cooler) before the raw water pump and hook a hose up there without damage? Will the hose pressure cause a problem or do you need to bleed some water off out the intake to ensure you do not over pressurize the system? |
Posted By: GottaSki
Date Posted: October-11-2005 at 1:04pm
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143 or something for salt water.
160 something for fresh water ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Tim D
Date Posted: October-11-2005 at 2:43pm
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If it doesn't want to start after sitting, check the exhaust manifolds. You may have a leak that is letting water in the motor. Most of the time holes will be on cylinders 1 and 5. Water doesn't burn or compress and this may be the case if it cranks slowly. ------------- Tim D |
Posted By: Guests
Date Posted: October-12-2005 at 1:45pm
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Thanks Tim. Actually it cranks fine just seems to be cold-blooded in that it doesn't just purr after a restart like my 302 does.
You have to run it a little above idle for a bit before you can idle in gear. I plan to check the whole system over next spring but figured I would try to tap the knowledge here for insights before I start poking around the carb and ignition systems. My other project coming up is a compression check to see how this motor is doing. It's pretty high hours and could probably use a top end this winter. Thanks Gottski, I was curious since the 302 in my other boat is dialed in with a 140 thermostat and it runs great. I'll look at available thermostats at Skidim and see what there is available for this motor. 180 seemed awfully high for a raw water system. Anyone have any insight into the hose connections to run this thing out of the water? I have a plunger hose connector that the PO built to go on the water intake but would rather just put in a fitting to connect to if I can so I don't have to climb under the boat in the winter to connect the water to the motor. |
Posted By: Guests
Date Posted: October-12-2005 at 1:48pm
OOps mispelled Gottaski, sorry about that... happy fingers and bad eyes... 
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Posted By: Guests
Date Posted: October-12-2005 at 11:11pm
| Maybe you should be looking at the carb and choke instead of pissing in the wind and worring about the T-Stat to fix your problem. |
Posted By: mackwrench
Date Posted: October-13-2005 at 10:27am
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Way to go 79, always can count on you to have just the right answer to make any guest here all warm and fuzzy,....But,
Mr. Fisherman, It does sound like the choke may need adjustment. My 65 mustang has a "tee" fitting at the trans cooler inlet hose with a 3/4 hose running to back of boat to a garden hose bib connection on the transom. I just hook up hose and run it. There is no valve to turn off, the psi from the hose feeds water to engine. Water does run out the pick up until it starts but theres more coming out both exhaust when running, I have a 140 t-stat and boat under load runs around 160. Welcome here and I am sure you'll enjoy your new CC. ------------- NO LONGER A MEMBER |
Posted By: Fisherman
Date Posted: October-13-2005 at 11:56am
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Thanks for the insight on the hose connection mount. I may not go quite as elegant and will just tee off the line and put the hose bib inboard.
As to the carb and choke, I concur, and this (as pointed out previously) is one of the other projects I have on the table. The T-Stat is just one of several items I want to work on this winter. At my age, I am not too concerned when someone responds like 79 did. I know he's got a wealth of knowledge so the fact that he responded at all is great. I'm the same way on the Mercedes diesel forum which I frequent when someone is chasing their tail instead of facing the problem...  ------------- Central Oregon '79 Ski Nautique '84 & '85 MBZ Diesels '79 Apollo 3000DB It doesn't need to run bad or look bad just because it's old! |
Posted By: Guests
Date Posted: October-13-2005 at 4:48pm
| If you want to add a tee I would suggest the flush-pro valve SKIDIM sells. The added fitting on the back is for convinance (sp) and more for saltwater applications where you have to flush the block after every use. But if you are going to use it once in a while the flush-pro valve is a cleaner install and all you have to do is raise the motor cover and connect the house. I would get a 143 t-stat and the gasket from SKIDIM, this should have your operating temp around 160, The gasket can be a little tricky getting the right one and some brands are a little thin and you have a leak problem or have to use RTV. I preffer the one vince sells beacuse I can remove the housing and reuse the gasket without a problem as long as you don't over torq the bolts or glue it down. Also you may want to get a Holley marine carb kit and re-build the carb over the winter should fix the hot start problem, just make sure you don't get teh float to high, some will argue that you need a wedge plate, I personally don't agree and have no problem running without one It all comes back to the carb being adjusted correctly. |
Posted By: mackwrench
Date Posted: October-13-2005 at 6:00pm
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Thats cool Fisherman, I have some experince on older Mercedes Diesels. They used to be used in Thermo-King Truck refer units...I am a diesel mechanic as well...Mack Trucks. Ever notice how most all gas engine people are "Gas Engine only" mechanics & diesel mechanics have to work on everything! ------------- NO LONGER A MEMBER |
Posted By: Guests
Date Posted: October-13-2005 at 6:07pm
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You are dead on.
I've had a '75 240D, '80 300D (naturally aspirated), '81 300SD and then finally my two newer (80's) 300SDs. I love the wya they drive but more importantly I love the fact that I can do "everything" to them without code readers or having to remove 15 plastic panels to find the injectors...
The PO of this boat installed a new accelerator pump and installed a rebuild kit. He also has adjusted the floats numerous times I guess but it still seems like it is not right. I think I'll just work through all the settings this winter and take my time on it. He really took good care of the boat so hopefully I can get many more years out of it. Thanks for the help/insights. I need to pick up a few things at Skidim and will look into that flush connector as well. |
Posted By: woody
Date Posted: October-14-2005 at 12:35pm
| I had a simular problem with my 1991 SN after a rebuild . I fixed the problem by replacing the two o-rings on the tube and o-ring assy( #42. on the holley Instruction sheet that comes with the kit .These o-ring don't come in the holley rebuild kit. I never considered replacing them when I rebuilt the carb. The tube seem to fit in tight enough . The boat would start awesome when cold , but was hard starting once warmed up . I could see a trace of raw fuel in the water at idle no matter how much I leaned out the carb. Once I replaced the O-rings My problems were over . |
Posted By: Fisherman
Date Posted: October-18-2005 at 9:57am
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Thanks for the insight woody!
I took the boat out this weekend and am now convinced that the floats are too high as the secondaries seem to be getting a little residual fuel dripping out of the tubes. I would guess this is due to the angle of the carb and high float settings. I think I will go ahead and rebuild this carb myself just to make sure it is done right. I do have a couple of questions about the 4160 carbs. First my carb number is not listed anywhere. Holley and all the lists that I can find on the web. The numbers off the airhorn are: 6R4863B P-66 I also found 9510G and 7463 stamped on the carb. Is there a cross reference or something that can tell which carb is actually on this engine or more importantly which carb kit I need to buy? There seem to be three or four kits for the 4160 and I have no clue which one I should get. Also I really like the idea of the externally adjusted float but the PO replaced the float bowl on the primary side and it is not externally adjustable. Can you get the externally adjusted float bowl for the 4160's? The only one I see is the standard one available. Is this something that I could post in the parts wanted section and get a response on? I'll try it anyway... One last item of note is that this engine has a flat spot out of the hole and the accelerator pump seems to be shooting fine. I'm thinking the secondary spring is weak so I will probably get the kit and try a different spring. Once again, thanks for the input...  ------------- Central Oregon '79 Ski Nautique '84 & '85 MBZ Diesels '79 Apollo 3000DB It doesn't need to run bad or look bad just because it's old! |
Posted By: Fisherman
Date Posted: October-18-2005 at 10:33am
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Oops, bad eyesight. I just rechecked those carb numbers off the airhorn...
D4JL 9510G List is 7163 3577 is under that. Sorry for the confusion... One more question though. The raw water intake line is 1 1/4 inches but the sherwood pump is only a 1 inch. Can I put a reducer in the line to go to the one inch size without messing anything up or will it cause a water pressure issue with the intake hoses to reduce down? ------------- Central Oregon '79 Ski Nautique '84 & '85 MBZ Diesels '79 Apollo 3000DB It doesn't need to run bad or look bad just because it's old! |
Posted By: 79nautique
Date Posted: October-18-2005 at 5:00pm
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Not sure if you are getting things confused a little but on most the hose coming from the hull pick-up through the tranny coller then to the raw water pump and up to the t-stat housing is usually 1" i.d. hose. And the hose from the bottom of the t-stat house to the elbow and circulation pump are 1.25 i.d. hose. On the carb not all models of 4160 carbs have the externally adjustable floats. I belive you can go online to summit racing or jegs and get new bowls that will work just fine. Typically if the carb is a double pump holley it has external adjustments for the float but on the single pump models they are internally adjustable. Holley has a pretty good online tech help so you might be able to run the model numbers by them and they can usually give you the part numbers that you would need. Just make sure the carb kit you get has a #65 power valve in it. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Fisherman
Date Posted: October-18-2005 at 5:22pm
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Thanks. I called Holley and they were great. Gave me all the info I needed along with information on all the extraneous parts I would need to go to externally adjusted floats. Think I'll just set them up like they are supposed to be and see if I cna get it adjusted right without leaking fuel. Right now it scares me to lift the boat cover off with a cigarette in my hand...
BTW - 79nautique, followed the link to your boat in one of the other posts. Very nice...
I though my boat was clean but yours is very clean... I also spoke to Vince today to pick up a few needed items including the FlushPro. Great guy with lots of insight. I measured the raw water intake hose today and it is 1 1/4 inch. It runs 1 1/4 inch to the tranny cooler and then 1 1/4 inch up to the raw water pump where the PO put a piece of tubing on the water pump intake to resize it to the 1 1/4 inch hose. I'm going to step it down to 1 inch just past the FlushPro after I get it installed so that no shim is required on the Sherwood intake. My wife is a little peeved that I have another project now (3 boats, a van, 2 mercedes diesels and a motorhome). But a guy just isn't productive unless he has things to tinker with... my opinion anyway. ------------- Central Oregon '79 Ski Nautique '84 & '85 MBZ Diesels '79 Apollo 3000DB It doesn't need to run bad or look bad just because it's old! |
Posted By: 79nautique
Date Posted: October-18-2005 at 6:14pm
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Thank you kind sir it took a little time and money but it turned out ok concidering how many hours are on it.
Sometimes you have to come in from the garage/toy room and spend time with the wife, otherwise you don't get to play with their toys. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Fisherman
Date Posted: October-18-2005 at 6:47pm
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LOL ------------- Central Oregon '79 Ski Nautique '84 & '85 MBZ Diesels '79 Apollo 3000DB It doesn't need to run bad or look bad just because it's old! |
Posted By: 25XS
Date Posted: October-31-2005 at 6:10pm
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Fisherman posted: <<...the raw water intake hose [snip]runs 1 1/4 inch to the tranny cooler and then 1 1/4 inch up to the raw water pump where the PO put a piece of tubing on the water pump intake to resize it to the 1 1/4 inch hose. I'm going to step it down to 1 inch just past the FlushPro after I get it installed so that no shim is required on the Sherwood intake. >>
Sounds fishy... (no pun intended, Fisherman) I wonder if the PO replaced the waterpump because mine runs 1-1/4" all the way to the raw waterpump intake... The PO of my boat had hoses running all over the engine compartment, including a raw water strainer basket mounted WAY high near the engine cover. There was about 9ft of 1-1/4" hose between the thru-hull fitting and the raw waterpump! I chopped it all out and started fresh. I routed the thru-hull fitting directly to the raw waterpump inlet; shortest route possible, to get the water out of the lake and into the pump asap. Then ran to the tranny and oil coolers and then into the engine and it's worked perfectly all summer. I eliminated the strainer basket all together and the boat's gone from eating three impellers per season to one impeller lasting all summer while I sorted out all the other problems. The impeller still looked new last week and I think it's because it's got water on it right away instead of having to pull water thru all the hose and two heat exchangers before pumping into the engine. Impeller pumps are MUCH better at pushing water than pulling water. ------------- "Stock Stuff" by day... Racing Mercury outboards on the weekends. 1991 Nautique Excel "thousands" of hours... |
Posted By: AWhite70
Date Posted: November-01-2005 at 10:44am
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25XS your statement "Impeller pumps are MUCH better at pushing water than pulling water" just isn't true.
What IS true is that centrifugal pumps (i.e. your engine circulating pumps) aren't good at pulling water. For this reason the raw water pump is added to the engine. The raw water pump is a style of positive displacement pump and positive displacement pumps work quite well at pulling water provided that they are set up properly. Sounds like you had other problems than just routing and if you continue with your current setup you could have more problems. The strainer is in front of the transmission cooler and raw water pump for a reason. To keep cr@p out of the system. The first time you suck up a twig, platic bag, etc. it's gonna wreak havoc on your raw water pump. I STRONGLY Suggest you go back to the OEM style setup of. Thru-hull fitting to strainer to tranny cooler to raw water pump. Anything else and you're asking for problems. |
Posted By: mackwrench
Date Posted: November-01-2005 at 11:59am
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My 302 doesn't have a circulating pump, It sounds like the way 25XS boat is plumbed theres more hose than needed. The stranier for sure should be reinstalled, I have seen EVERYTHING you could think of in one, it'll only take one small leaf or a few cig buts to cause it to run hot. These boats are useally plumbed hull intake to strainer (mounted lower than raw pump on stringer), strainer to cooler(s) cooler to raw pump. I bet theres not 4' of hose on mine this way. ------------- NO LONGER A MEMBER |
Posted By: AWhite70
Date Posted: November-02-2005 at 5:06pm
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Although I can't say it's impossible but I've never seen a marine engine without a circulating pump.
The circulating pump is the "normal" engine water pump at the front of the engine. It is in the same location and serves the same purpose as the water pump in an automotive engine. |
Posted By: 25XS
Date Posted: November-02-2005 at 5:59pm
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AWhite70: Put your money where your posting is. My statement, "Impeller pumps are MUCH better at pushing water than pulling water" is most certainly true. If you require proof I will send you a couple thousand flow curves for Jabsco, Sherwood, Johnson, FloJet, Perko, or ShurFlo to prove it... They are ALL based on head pressure at the inlet to the pump.
I do agree that a strainer between the thru-hull fitting and the pump inlet can be a necessary item, but not in all cases, and not if it's mounted too far above the waterline. I also know there should be a trap or loop of sorts designed into the hose before the raw waterpump inlet to keep the impeller wet between starts (drain that trapped water when winterizing!!!) but just a little higher than the pump inlet, not to the top of the engine compartment. A. I can't find a rubber impeller type pump that will draw vacuum pressures as strong as they will pump outlet pressure. B. Rubber vane type impeller waterpumps are designed to be BOTH post*tive displacement (low speed) and centrifugal pumps (high speed). The length, stiffness, and number of impeller blades is how the mfgrs change the interface from postive displacement to centrifugal. Didja know Carl Kiekhaefer, founder of Mercury Marine was the first to use this technology in a boat motor (1940) and it's hands down the industry standard now. C. Raw waterpumps are added to marine engines most obviously to provide water to the waterjackets/cooling system, but many don't realize they are also there to increase cooling system PRESSURE so the engine's (centrifugal) circulating pump vanes don't cavitate, which can happen at any water temperature, but more likely in higher temps found in the engine. Boat engines often run higher cooling system pressures than a car (15psi typical) because they don't have the added 'anti-boiling' antifreeze in them. That's why we're stuck with 140F and 160F thermostats instead of 190F+ like cars. The higher system pressure keeps hotspots from flashing to steam due to the higher pressure. D. There was no OEM strainer on my boat, just an aftermarket job added later, and it was located WAY too high above the waterline where it also drained when the engine was off. My raw water pump was having to evacuate several feet of air every time the motor was started and it cut the life of the impeller drastically. E. Frictional resistance to flow is the same in the raw water cooling hose routing no matter how you route it, so shorter runs and getting the water to the raw waterpump inlet quick as possible increases the life expectancy and flowrate/pressure from the raw water pump. This statement is true because the higher suction the pump must create just to get the lake water to the impeller (long hoses, heat exchangers, strainers, etc...) the lower the pumps total flow capacity will be for a given application. Let me know if I missed anything... I'm sure I did, but the gist is that you want the rubber impeller inlet wet as soon as possible when you dunk a boat after a long dry spell and all the crap routed before the pump inlet is killin' your potential. ------------- "Stock Stuff" by day... Racing Mercury outboards on the weekends. 1991 Nautique Excel "thousands" of hours... |
Posted By: mackwrench
Date Posted: November-03-2005 at 6:40am
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AWhite, My engine does not have a "circulating pump" My enging ONLY uses the raw water impeller type pump for cooling. Where the normal automotive type pump would be, their is a speical timing cover for this engine, it has "intercepter" cast in it, along with a hook up for a cable driven tachometer that ran of the camshaft gear.
My old (1965) correct craft was not OEM with a strainer, I installed one after a few times enginge ran hot from leaves in cooler inlet. I do not agree however there should be a "loop" or trap to hold water, The strainer should be mounted as low in the hull as room permits, using as short as pick up hose as possiable. the type of strainer I use holds water, and provides enough to wet the impeller before the lake water arrives. The key to this I belive is use as short of hose for inlet to raw pump to minimize time impeller is ran dry. And we all have to understand the raw pump impeller is a maintenance item that should be replace from time to time depending on your use. ------------- NO LONGER A MEMBER |