1970 85 horse overheating issue......

[riverkid]

Well,I've got a new water pump,housing,and lower unit seals.This beast ran fine and cool for the past month.Now of course,being a holiday weekend with some time off,it's overheating...I've pulled the hose off the starboard cylinder outlet and verified water flow on muffs in the driveway.It's fine.I had to pull that hose to make it back home last time out,so, I figured vernatherm or relief valve,right? No dice.With the hose removed and running in the water,(no muffs)I get very little water out of the thermostat housing.This water is mixed in with slimy exhaust drippings too.I've flushed the water tubes with the garden hose.stuck the hose into the port side water inlet on the head,done most everything I could think of-is it a gasket or seal in the lower unit that is leaking and not allowing the water to make it up into the block??(the reason for the slimy water in the thermo housing??) I've got Seloc manuals,Clymer manuals,and a '72 85 horse 'Rude factory manual-I'm still lost for a cure.Help!!,C.C.

 

[Solittle]

Re: 1970 85 horse overheating issue......

There is no "seal" in the lower unit. I would suspect that the water tube connecting the water pump to the power head is not seated properly or the thermostats are stuck or both. You could pull the thermostats out and run it to see if that cools it down.

 

[riverkid]

Re: 1970 85 horse overheating issue......

Thanks there,ahh,,SoLittle.I'll explain a little more for you..There are two water tubes coming up from the water pump housing-they are intact and doing what they should be doing. This paticular year motor has one thermostat,or,"vernatherm" to be more precise.Wether thermostat is installed or not,it still doesn't flow enough water to cool the powerhead.The water pump has about 10 hours total on it-it looked brand new as of this afternoon.I still haven'f figured out your your opening sentence-"no seal in the lower unit"....I'm left wondering what REALLY happens in Miami..

 

[OBJ]

Re: 1970 85 horse overheating issue......

Hi riverkid. The slimey stuff in the water, look like oil? Maybe telling you got a leaky head gasket blowing exhaust into the water passage. Or an outside chance of the exhaust cover gasket leaking....but I would look more at the head gaskets. Does either head get hotter than the other....I'm mean hot.<br /><br />I think Solittle was refering to the water pump not having any seal that would be causing the problem......Miami's OK.....it justs gets blowed off the map on occasion from passing hurricanes....

 

[ledgefinder]

Re: 1970 85 horse overheating issue......

Your pump's not pumping, riverkid. On the muffs, you'll get flow even with a defective impeller due to your house's waterpressure. But the fact that you get no flow when running in the river, even when you pull a hose from the head, shows the pump isn't pumping. Pulling a hose makes those 1-thermostat/1-venostat systems act like the thermostat & venostat are stuck open. Hate to say it, but it's time to pull the lower unit again & see what's going on. Is the key still in there, driving the impeller?<br /><br />On the plus side, when you get it running, try the CT river in Brattleboro. Bit of a drive for you, but a great place. State has a ramp on the north end of Brattleboro, you have to drive through a corn field to get there, but it's good ramp. You can run from the dam near the NH line, about 20-25 miles up river, into the mountains. Lots of natural sand/gravel beaches, hardly any boat traffic. It's a little cold (my kids call it 'the Connecticut shiver' but good swimming & skiing anyway.

 

[riverkid]

Re: 1970 85 horse overheating issue......

hey,ledge.we're gonna' rent a joint up in Vermont this august.I may just check that out.Anyway here's the story.At 8 am today I pulled the lower unit off and guess what??? The lower unit dun' seized right up on me!! well,I reckon I didn't have any splines left in the crankshaft anyway,so;I unbolted the OMC controls and the rest of the motor and tossed them aside..I lugged out the 40 year old Merc,bolted everything up,fiddled with the control adjustments and I'm back in business!! I'm not knocking OMC,or endorsing Mercury or any other type of motor,but I do love my Merc.It's really too bad about the V4 'Rude;but I didn't have alot of $ invested in it and it pushed the Whaler like a rocket,probably faster than I would of ever needed.If you study up on hull design,there's a term called "hull speed",which if I remember correctly,(correct me,please)is the maximum you can push a certain hull design before they get unsteady and "twitchy".Well,my hull was certainly at max speed with the big OMC,so I figure it was kinda' wasteful (and noisy) having 85 horse instead of 60.I know lots of folks like to have maximum horsepower,but I guess I'm too conservative now,In my old age,Thanks,Everybody,C.C.

 

[ledgefinder]

Re: 1970 85 horse overheating issue......

Another V4 bites the dust!! The powerpack and the control box might be worth a few bucks on eBay. <br /><br />Hey, the directions to that boat ramp are (if I remember right), take Exit3 off 91 at Brattleboro. Get on Route 5 N, take that a mile or two, then take the last right before Rt 5 crosses over I91. On the road on the right, there'll be an auto body place, and a day-old bakery. Just keep going on that road to the river & the ramp. You'll go down a hill, cross under some railroad tracks, drive along the edge of a cornfield (don't remember in what order), then you're there. If you head south in the boat, Brattleboro has some restaurants & ice cream places you can dock at. If you head north, the river winds around & heads up into the mountains. I never found a navigation chart for this section of river. The locals told me where it gets shallow up north, but I don't remember now - it's a ways. Be careful, though, obviously until you get it scouted out.