Engine Cooling

[Joel]

Of course its never anything THAT simple...      Got the same temp readings while out on the lake yesterday.  The good news is the boat is running like a champ      Had to gas up and the Marina only uses gas with NO ethanol - I'm sure my boat likes that    The shop ordered a new impellor that should be in before next weekend.  I'll put it in and go skiing then - any excuse to go skiing 

Lets hope # 1 its the correct impellor and # 2 it solves the overheating issue.  If its the correct impellor, but it still overheats then I'm out of ideas, other than going commando and removing the T-stat all together - which treats the symptoms, but not necessarily the problem (which is what Ron is sayin).

I'll let you guys know what I find...  Hope you all are having better luck 

[Joel]

Well damn!  Installed the new impellor...  fits snug, all the way to the face plate with no gaps, new gasket, etc.  Ensured all the hose connections were tight from the hull intake to the exhaust risers.  Took it out on the lake and the boat ran HOTTER @ 180 - 190 F.  Although it stayed consistent and didnt fluctuate more than 10 degrees between underway and idle...

So out of shere desperation, I took out the thermostat and it ran at a VERY cool < 100 (underway) and 110 (idle).  It still runs O.K. but the motor wants to hesitate out of the hole cause she's not warmed up...  I'm gonna go to NAPA and try out another 160 F thermostat - hoping my other NEW one is not opening fully at 160 F (thier cheap).

If that doesnt work, I'm officially out of ideas short of pulling the recirculating pump.  The recirc pump appears to be fine, its not loose, not making any noise & turns smoothly with the belt off, etc...  Is there a chance the recirc pump's blades are worn to the extent that thier not moving the hot water well

Its not like the boat is overheating @ 180 F, but its driving me nuts cause it SHOULDNT be that high...

Thanks guys!  Joel

[John Doerfler]

Joel I FEEL YOUR PAIN MAN!!!!!!  I have been going over the same problems all summer and eventually gave up after coming to the conclusion that I think my water pump isnt putting out enough pressure.  The boat runs great without a stat staying around 130ish but I want my boat to look and run just like it came from the factory and it drives me nuts that I cant figure it out.  Going to sit on it all summer and maybe try buying a whole new impeller pump next spring (expensive!!).  About the circulation pump, I bought 2 new pumps, tried them both with no success.  I doubt its your circulation pump but they are cheap and its worth a shot I guess.  Let me know if you finally figure it out.
John Kyle Doerfler

[Mike Harry]

try buying a whole new impeller pump next spring (expensive!!). 

Shouldnt be that expensive. I got a whole new one (housing and all) for 200. You can buy rebuild kits for them for around 35 to 40 bucks. I just went the easy way out..... gonna rebuild the old one and stash it somewhere on the boat for a backup plan.

[Joel]

Went back to the parts store today and got a SUPER-DUPER (limited lifetime warranty) 160 F T-Stat...  If this doesnt solve the problem I'm just gonna run it at 180 F this week and worry about it another day...

I already have one Jabsco & one Johnson impellor.  Ron is correct, the Johnson is TIGHT but works about 10 degrees cooler (according to the temp gauge) probably because of the improved pressure Ron referred to in another post.

The only other item I can think of is the temp sending unit maybe off (doubtful, but you never know).  I'll post results of the new T-stat after I get back to Ohio - I'll include make/model #/etc - from our week long boys boat trip on Laurel Lake, Corbin, KY.  Beautiful lake but very limited ammenities and its in a DRY COUNTY - MAJOR BUMMER... 

[John Doerfler]

I have the 350Chevy in my 83 and that requires a larger pump than the 351ford motor due to the increased performance.  As a result it is more expensive at around $380.  I think thats what Ron told me.  Anyway I installed a rebuild kit and it didnt work.  Its a long story.  Later.
John Kyle Doerfler

[Mike Harry]

I have the 350Chevy in my 83 and that requires a larger pump than the 351ford motor due to the increased performance.  As a result it is more expensive at around $380.  I think thats what Ron told me.  Anyway I installed a rebuild kit and it didnt work.  Its a long story.  Later.
John Kyle Doerfler

Mine is the Indmar 350 also with the higher horses..... which only came in barefoot boats in my model. The pumps may very well be different though.

[John Doerfler]

Dont you love the 350chevy?  Mine is the Hardine Marine.  Maybe thats the difference?
John Kyle Doerfler

[Joel]

Nope...  Love my Ford motor...      Bulletproof and runs like a champ (hot or cold)  I'm off for a week long water ski trip in the a.m.  You guys keep it lively on here and I'll check in on Monday...

Ciao!  Joel

[Joel]

Discount Inboard Marine has a 143 F thermostat listed for less than $10.  I believe it fits both the Ford 351 and Chevy 350.  That'll be my next purchase    I'll let ya know how it works!

[Joel]

Sorry, I almost forgot...  DIM lists the correct impellor for our boats as well 

[Joel]

Well, guys its been a while since i was on, but the 143 F T-Stat works like a charm     She runs at 150 and the temp stays pretty steady.  But, as Ron has said MANY times - I'm treating the symptom and not the cause...  So, after looking around with the engine OFF, I noticed a leak from the back of the impellor pump.  Gotta say I never noticed that before, but that is probably where the system is sucking air - Ron is a damn genius!!!

Anyway, can I repair the rear seal in the pump or do I need to get another pump???  They aint cheap   

Thanks brothers!

[Joel]

Good news!  The raw water pump had a leaky rear seal and one (of two) bearings starting to bind-up.  Fortunately, I caught it before both bearings went bad so the pump housing and shaft wasnt damaged.

A new Johnson pump is $245... NOT!  The rubber seal was $18.25 + S&H, the two bearings were $25, my labor is free...  Less than $50 repair - PRICELESS!!!   I'm a happy camper.

Cooling issues SOLVED!!!!

[John Doerfler]

Good to hear Joel!
John Kyle Doerfler

[Mike Harry]

Back from the dead.....over the summer I've had the reverse problem as you guys. I'm running a 160 Tstat. And my engine wont run above 125..... have confirmed with infrared thermometer.

Think my stat is stuck opened.

Any other thoughts?