351 overheating |
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FootFever78
Newbie Joined: September-22-2014 Location: Cicero, IN Status: Offline Points: 24 |
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Posted: May-03-2015 at 3:27pm |
Bought a 92 excel last Fall with a 351 in it and spent the winter reconditioning the boat. This is my first inboard. I ran the engine last week and unfortunately did so without the drain plugs reinstalled (I didn't remember they had been taken out for a quick winterization) Put the plugs in, put in a new strainer with an O=ring, put in a new impeller, and took the boat to the ramp. Engine heated right up to 220. Brought it back to the house and ran it with a garden hose pushed in the hose that goes from the strainer. The boat temp came down to 160. Then replaced that hose on the strainer, and detached the hose from the intake and shoved that in a bucket. It sucked the water in and ran fine at around 160 - 170. Also put that hose down the intake coupling and blew a bunch of junk out of the intake. Thought that was it - took to the ramp and it overheated again. And that's where I am at. I am very coachable here, and while I searched and reviewed threads on "overheating", I wasn't able to locate the same symptoms, I would happy check out any threads someone already knows of. Appreciate the direction.
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Jim,
It sounds like you did the needed checking but go over your hoses again. No screwdriver on the hose clamps. You can't get enough torque. Use a nut driver or socket. Overheating at idle indicates sucking air someplace but it could also be a blockage. Check for bits of old impeller at the T stat and at the trans cooler. Was the old impeller busted up? Do use an OEM impeller and not one of the aftermarket ones like Sierra. There are known problems with them. Sucking from the bucket is the best method for troubleshooting since problems aren't masked by direct pressure from the hose. You did find all the missing plugs correct? Welcome to CCfan. We always ask for pictures so when you get the heat issue fixed, post some! |
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FootFever78
Newbie Joined: September-22-2014 Location: Cicero, IN Status: Offline Points: 24 |
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Thanks Pbrainard. I did find bits of the old impeller in the housing. I meant to mention that I did check the tstat, which was busted. In fact, half of it (the coil part) wasmissing entirely. Could that be causing a blockage? I replaced that with oem tstat from N3 Boatworks. I did verify the nuts are all back in. I will go over the hoses again with the socket And check the bucket approach again. Will report back asap. Thanks again!
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Pretty unlikely but sounds like it wouldn't hurt to check the actual intake. Maybe someone bottom painted over it or something.
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FootFever78
Newbie Joined: September-22-2014 Location: Cicero, IN Status: Offline Points: 24 |
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Update: Checked the strainer and hose from the intake. At idle with a garden hose pushed into the intake end of the hose, there were no bubbles in the strainer. When revving, the bubbles began appearing in the strainer. My next move is to bypass the strainer all-together. The intake hose also looks suspect so I'll be replacing that and all other hoses asap. The intake looks clean now. Will provide another update once able to bypass the strainer and test. This sucker really wants to run. Hopefully I can replace the strainer if needed and/or o-ring(s) and be off the races.
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halfnelly
Senior Member Joined: January-14-2013 Location: Maitland, FL Status: Offline Points: 253 |
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Try running the intake hose and a garden hose into a bucket instead of hooking it up directly to the garden hose. When hooked up directly, the garden hose will supply enough water at idle, but as the pump speeds up it will either pull air or collapse the hose. Using a bucket is much more of a real world simulation to see how much the pump pulls on its own without water being force-fed into the pump. |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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You can definitely buy a new OEM strainer. Zach can hook you up.
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3735 |
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I had strainer issues last year. My Oring was not sealing. I filled the Oring slot with silicone, Wiped the clear cover with a thin film of Vaseline and bolted it together and let it cure. It works now and the cover is still removable, but now it seals on silicone rather than the O ring. If I had a spare O ring on hand I would have used it.
On torqueing the hose clamps, the intake hose is large and stiff, nearly impossible to clamp it cold. Warm the engine and the hose if possible and tighten it while warm and you will get a good clamp. If you don't have a good hot sun and a warm engine to work with a hair dryer can heat the hose up pretty quickly. You will be surprised how easy it is to clamp while warm, it gets more flexible. |
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spiralhelix
Senior Member Joined: August-06-2014 Location: IL/WI Status: Offline Points: 496 |
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UPDATE: I stand corrected. disregard the suggestion below.
fwiw, when we had water pump issues, a buddy just replaced all my intake lines from the through hull to the t-stat housing with 1" I.D. clear braided vinyl tubing. Every time i start the boat, first thing i look at is that water is flowing from the through hull intake, through the strainer, trans cooler, RWP, to the t-stat. piece of mind for $20. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Careful - it may collapse. Wire reinforced has been mentioned many times here.as the recommended replacement |
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spiralhelix
Senior Member Joined: August-06-2014 Location: IL/WI Status: Offline Points: 496 |
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yes. in my head I had reinforced, guess I typed too quickly. Thanks for the catch Pete.
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13513 |
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Braided clear vinyl and wire reinforced rubber are not the same.
Bubbles off the hose are because the house pressure isn't enough to supply a revving RWP, not idicative of any air leak. |
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Waternut
Senior Member Joined: July-11-2012 Location: Macon, GA Status: Offline Points: 292 |
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Did you ever figure out this problem?
The clear braided hose is usually pretty stiff at 1" ID. Theoretically, clear braided is really meant to assist positive pressure (inside out). Wire reinforced is meant to resist vacuum (outside in) and resist kicking. Considering the low pressure dealt with in our boats, both are plenty stiff and both resist kinking pretty well. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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John, Your stating the intended purpose of the tubing or hose is correct. You being an engineer I'm sure will also agree that the hg" vac ratings (not low pressure) of each are important before selection for suction sides of any pump. On the suction side of the RWP, I do not suggest anyone to use the braided vinyl tubing "Joe Schmo" found I'm sure at the hardware store. On the pressure side of the RWP has issues as well. Yes, it's braided to resist pressure but it gets real soft as temperatures go up and the reason ratings are given along with temperature. |
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FootFever78
Newbie Joined: September-22-2014 Location: Cicero, IN Status: Offline Points: 24 |
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All good coaching here. I bought the vinyl reinforced hose and plan to use for diagnosis. Really liked the clear hose idea to sight air pockets, etc. If new hose solves the problem I will replace with the right hose. I am desperate for a smooth running, dependable ride. Until that happens, I will be trying most anything. It's function over firm at this point.
Thanks all for the coaching. I hope to have a positive report tomorrow afternoon as that will be my first chance to wrench in a week. First world problems.... |
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cmacbuck69
Senior Member Joined: June-19-2013 Location: Jax, FL Status: Offline Points: 105 |
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I have been having similar issues with my 83 SN. Did the same checks and all is good with the impeller, pump, t-stat, strainer o-ring etc... I pressurized the system with the garden hose and found no water leaks. Then with the bucket water test in the driveway, the RWP was pulling very strong (so the RWP is ruled out for now) yet I was still up around the 200 degree area. Then I checked the circulating pump and the pulley has a bit of wobble to it telling me that the bearings are going bad and it is struggling to take the raw water and push it through the block. Curious if I am on the right path, any thoughts?
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Chris,
You could be heading in the proper direction but I would not rule out there is still a problem with sucking air. You pressure tested the system but air can get sucked in whereas water will not be pushed out at leaks. . Where you connected for the bucket test will also make a difference. Was the strainer and hose to the pick up included? |
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cmacbuck69
Senior Member Joined: June-19-2013 Location: Jax, FL Status: Offline Points: 105 |
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Peter, yes it was connected to the hose on the intake side of the strainer. The strainer o-ring is brand new.
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Chris,
Have you checked the T stat to see if it actually works? The old school method is to put it in hot water on the stove along with a thermometer. While you have the T stat housing open, check for chunks of old RWP impeller. |
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cmacbuck69
Senior Member Joined: June-19-2013 Location: Jax, FL Status: Offline Points: 105 |
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The engine was completely rebuilt with a new t-stat and impeller, but still ran both of those checks and both were good.
Another interesting fact that I have struggled to process is that the water leaking out of the strainer lid last weekend before the new o-ring was installed was too hot to touch, at the strainer. Points back to circulating pump not pushing water into the engine and heating up the water on the suction side of the RWP... May be reaching here but nothing else makes sense. |
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kytom2
Gold Member Joined: July-25-2007 Location: Maysville Ky Status: Offline Points: 698 |
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I don't think water in the strainer should not be hot. Water in the strainer is straight from the lake.
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cmacbuck69
Senior Member Joined: June-19-2013 Location: Jax, FL Status: Offline Points: 105 |
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Exactly! So how could it get hot? My theory is that the circulating pump was not circulating the raw water into and out of the block. The RWP, doing all or most of the work, could not replace the hot water quick enough with raw water so the heat build up made its way upstream into the suction side... Any ideas?
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jhersey29
Senior Member Joined: February-20-2014 Location: Colorado Status: Offline Points: 272 |
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Can we get a video of the exhaust water output when on the bucket or hose?
Here is a video of a GT40. 351 but with EFI. Block is probably about the same, water pump is the same I believe. https://onedrive.live.com/redir?resid=f02b1d32fd09adf0!20367&authkey=!AO6q_AujpeoYyuk&ithint=video%2cmp4 |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Chris,
You mentioned the engine has been rebuilt. Check the routing of the plumbing to make sure it was installed properly. How about posting some pictures especially the hose around the RWP. Even though you did a bucket test, are you sure the RWP isn't installed backwards? |
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cmacbuck69
Senior Member Joined: June-19-2013 Location: Jax, FL Status: Offline Points: 105 |
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Unfortunately I don't have videos of the discharge and I'm out of town this week.
The plumbing routing is correct. It's a reverse rotation engine and the RWP screw is to the outside. The arrow on the strainer is also pointing in the correct direction. Water flow through the tranny oil cooler is opposite the flow of dex. |
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FootFever78
Newbie Joined: September-22-2014 Location: Cicero, IN Status: Offline Points: 24 |
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Update: I installed new hoses (clear with braided reinforcement) so that I could see what's happening.
I bypassed the strainer, ran a hose into a bucket full of water. Engine fired right up, ran to temperature, sucked in water no problem. I then re-installed the strainer and put the intake hose in the bucket to run the same test, and the engine only sporadically sucked water before stopping all-together. (all of this was done in my driveway) Figuring the strainer had a leak, I took the boat to the ramp and ran a hose from the intake to where the strainer hose normally attached to the engine (can't recall that part name). So no strainer. The boat sucked water up to the top of the hose but would not suck water consistently, not even for awhile. Very frustrating because I thought I had it isolated to a faulty strainer. So now I am thinking I may have smoked the impeller somewhere along the line and that it needs replaced. I'm going to check that tonight as I ran out of time yesterday (Mother's day obligations). My question is this: Could my other water pump (not the RWP) be bad? Is there a way to test that before buying a new one? |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Ski dim mentions a way to check the circ pump:
http://www.skidim.com/Faq_TROUBLESHOOT.asp#RWTS It's #6 of the overheating troubleshoot. However, I don't think a bad circ pump would have an affect on the RWP's ability to pull water from the lake/bucket. |
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kytom2
Gold Member Joined: July-25-2007 Location: Maysville Ky Status: Offline Points: 698 |
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In my mind the only way you could get hot water in the stainer, is the rwp is putting it there. That would mean you have a hose on backwards.
How would you be picking up any water to go thru the block to get heated up? The only water intake would not being used. Instead you would be trying to push water out of the water intake thru the strainer. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Tom, Gravity! As the boat is pulled out of the lake, some of the water in the engine runs backwards. |
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13513 |
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Don't think so
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