1996 Four Winns Sundowner with 5.0 Cobra engine and drive

[Lpgc]

Not sure if the boat has been used in salt water, I know the last owner used it only on fresh water and some people have said the drive etc seem in too good condition for it to have been left for long in salt water. So far I've only used it on fresh water but I do plan on using it on salt water, though I won't be leaving it moored on salt water for longer than (say) a week at a time.

I wonder if the Salt Away stuff would shift rust?

I don't think I'd want to remove the water pump just to flush the engine, if I were going to remove the water pump I'd probably pull the engine out of the boat first. But I understand your idea about being able to reverse flush if I did that.

I suppose any filter would need a big enough surface area not to restrict flow if it started collecting some debris, with big enough holes not to collect tiny bits just bits big enough to cause a problem for the thermostat. One problem for the filter idea is I expect (because most vehicle engines pump to the top of the rad, bottom hose is where cooled water returns from the rad) the flow direction will be from the water pump to the stat housing then down through the wide rubber pipe to the bottom inlet? If that is true the water containing debris would already have gone past the stat before going through the filter... and if it goes past the stat the stat could be open and the debris could still get stuck in it and hold it open. But still I'd expect a filter of suitable spec to have a positive effect if placed inline with that wide diameter rubber stat to water pump pipe.

 

[Lou C]

The way the water flows the stat housing is basically a gate & switching valve….cold water comes in from the impeller and gets passed thru the exhaust system until the stat opens. Once the stat opens then hot water starts to exit the engine via the exhaust and at the same time cool water from the impeller is pulled into the flow created the front circulation pump. So with that big hose from the stat housing to the circulating pump the direction of flow is out the housing and back into the engine. Not sure how to make a filter work given the water flow pattern.
Next thing to research is cooling system cleaners. I think there are automotive cooling system cleaning solutions that might work to clean the rust out of a cast iron engine.

 

[Lou C]

this is the same for both the GM and Ford engines, even though the Ford uses that additional adapter to adapt from the vertical water outlet on the Ford intake manifold
You can see why when I install a reman engine one day, it has to have closed cooling. No more corrosion in the block, pressurized cooling system, better efficiency.

 

[Lpgc]

Thanks, I think I understand how the system works but wasn't sure if the water flowed up or down through the wide diameter pipe to the circulation pump.

I was thinking was there will always be a lot of water recirculating even when the stat is closed. During time the stat is closed any rust that comes loose is going to keep circulating. When the stat is closed nothing will flow through it, when partly open is when there's the highest chance of it getting clogged. A filter in the wide diameter pipe would remove some of the rust circulating.

I would prefer a closed cooling system for the reasons you listed, it would also free up being able to fit a more conventional or more modern water pump, inlet manifold, thermostat housing, etc on the engine and could fit better/lighter aluminium heads for more power.

 

[Lou C]

Yep and a high performance Edelbrock intake manifold, although some of these have a brass liner in the cooling passage so they can be used with raw water cooling. My other motivation is to make winterizing less of a chore.

 

[Lpgc]

Used the boat on the river for another couple of days and a total of around 70 miles again, this time we went further up the river where there are fewer boats and fishermen to moan about breaking the speed limit. Maintained 30mph at around 3000rpm for 20 minutes no problem but when I opened her up to 40+mph and 4200rpm the engine seemed to occasionally sputter or lose power a few times after around 1 minute. I didn't want to risk an engine stall, getting stranded or damaging the engine so I backed off to a steady 25/30mph and it ran OK again. Wonder what could be causing the problem (fuel or ignition)? I didn't notice a problem with sticking one-way valve when I tested it, filter looks clean. I later changed the distributor cap and rotor arm but haven't tested running flat out again since doing that.

Another thing I've noticed is that the engine won't hot start unless I give it a little throttle, if I give it a little throttle it always starts fine when hot. Is this normal or should it start without any throttle?

Same problems with the thermostat getting stuck open and the engine running too cool much of the time. It did run at 140F for a while but mostly ran at 130 or 120. Looks like I'll be cleaning rust out of the thermostat again...

 

[Lou C]

Having to give it a bit of throttle is totally normal all my carbed US cars were like that.
The high speed miss could be a bit of crud anywhere in the fuel system, anti siphon, fuel pick up tube (if this has a screen on it they can clog) carb needle valve, sticking float etc….
Also might check the the ignition secondary system as well, distributor, cap, wires etc. What distributor do you have? If OEM it might be the Prestolite BID system I’ll have to look it up. That system is an update from the old points distributor I have with an electronic module, but still has the old style mechanical advance system with flyweights and springs under the points plate. There is a lubrication wick in the dist shaft that you can see when you pull off the rotor this gets a few drops of oil a season that lubes the flyweights & springs & keeps them from rusting. I’ll try to look it up & see what you have….

Ok checked it what you should have is the Prestolite BID. Electronic module with centrifugal advance

 

[Lpgc]

Thanks Lou,

Yes it is the Prestolite with electronic 'points' (not mechanical points).

I haven't lubricated the weights yet, how is that done?

It didn't seem like a misfire, seemed more like the mixture gradually got leaner.

But when back on the jetty near the slipway I changed the dizzy cap and rotor arm anyway, I already had the new parts in the boat but decided not to change them before I tested the boat because I knew that at least the old dizzy cap and rotor arm worked last year. The old cap and rotor arm are not in terrible condition but have a bit of black crud / corrosion on the contacts. It didn't seem to run bad at all with the old cap and rotor arm but it seemed to idle smoother after I'd changed them. Haven't tested it yet with the new cap or rotor arm, only driven the boat from the jetty onto the trailer since fitting them. I do have a new set of plug leads, nearly changed them before first testing the boat this year but the new leads are a bit tight to get on the plugs with the marine exhaust manifolds, still I don't think the problem will have been the leads or ignition system, seems more likely fuelling.

 

[Horigan]

@Lpgc, This is unrelated to the topic above and I can't remember if this has been mentioned in this thread. One thing to watch out for on these engines is corrosion of the fuel reservoir water ports. The fuel reservoir is on the back of the engine, right under the power steering cooler. There is a U-shaped hole between them. On mine the raw water port on the back of the reservoir (facing aft) was completely corroded and barely held the hose on. Tell tale signs are bulging of the hose near the clamp. If this fails you loose raw water flow to the engine and it gets dumped in the bilge. It's part number 3854149 (item 21 below). Good luck finding one if you need to replace it. I was lucky to find one with much less corrosion, that I rebuilt with JB Weld. It may be the reason I end up going to a carburetor.

 

[Lou C]

OP has a simple Holley 2bbl not the EFI. I’d prob go thru the carb again & carefully clean the jets, passages & air bleeds. Replace all gaskets & install a new accel pump diaphragm

 

[Lpgc]

Thanks @Horigan, I appreciate you trying to help but as @Lou C says my fuelling setup is the Holley 2bbl.

I haven't had the carb apart and I left it in the boat all winter when I had the engine removed. After rebuilding the engine all I did to clean the carb was put some fuel in it and open/close the throttle level to work the accelerator pump. Maybe there is a problem with it, I do have a rebuild kit ready to fit but wanted to get back on the water quick after putting the newly rebuilt engine back in and thought it better to test the engine with the carb in the condition it was in last year (seemed to have no fuelling problems then) rather than risk making a mistake during the carb rebuild which could've delayed me getting back on the water or left me guessing if any problem was with the rebuilt engine or rebuilt carb.

I'm not familiar with these carbs, is there some component (e.g. a jet) that is only active at higher engine loads?

When cruising at around 30mph I still seemed to notice a gradual reduction in power, if I'm right about the power dropping off what could cause it?

 

[Lou C]

Power valve is supposed to open at a specified vacuum level and enrich the fuel mix. Head over to Holley.com there are many videos & info on how these carbs work. Probably 85% of all the carbs on Hot Rods & many classic cars are Holleys because they are a standard design modular carb in production over 50 years. Parts ate everywhere.

 

[Lpgc]

Yes I'd bet most people on the planet know about Holley carbs lol, I don't know much about specific features though. I was meaning to take another look at the Holley website if/when I got around to rebuilding this carb, I'll look sooner now, thanks.

 

[Lpgc]

Been a while since I last posted here but I've been using the boat and it's still running well.

Planned on using it on the sea or lakes but the weather hasn't been great so, so far, I've still only used it on a local river.

Still had the same problem with the engine not staying hot enough, seemingly due to the (new) thermostat getting stuck open with bits of flaky rust. Tried the old thermostat again which unlike the new thermostat has a bit of a groove cut in it, I thought the groove design might help bits of flaky rust pass through it and not hold it open. With the old stat fitted the engine did stay warmer and closer to normal operating temperature with 140F reading on the gauge at low throttle settings, so at first I thought fitting the old stat had cured the running cool problem, but when I got it on the plane the temp gauge slowly increased to 190F which was a concern so I slowed down. I've now refitted the new stat but haven't used the boat again since.

Does it seem likely that problems are just the old stat is broken and not opening when it should, while the new stat is as said just getting stuck open with rust/debris? Seems too much of a coincidence that it only started getting too hot when I fitted the old stat, so I'm not too worried that the raw water pump might be failing... Or should I be worried?

 

[Lou C]

190* F is too hot for raw water cooling because in the water passages around the exh valves which is about the hottest it can get you could be seeing over 200*!and get localized boiling. I think your old stat is not opening all the way. The new stat, what’s the rated opening temp? I have used both 160 and 140 stats and actually prefer the 160 because with the 140 it took forever to warm up. It’s a compromise between too cold (condensation and fuel dilution in the oil is a concern) and too hot (calcium deposits can start to clog the cooling passages). Based on 20+ years of salt water use & pulling the old heads off 7 years ago for me the calcium deposits are not at a level that caused overheating so I continue to use the 160 stat which gives temps of 160-170 or 175 at the most. When I do oil analyses I get no water or fuel dilution on the oil so I feel I’m on the right track. For you I’d try to figure out a way to really flush all the rust that may have accumulated ans when you store it for winter fill the engine & exhaust with propylene glycol antifreeze instead of just draining & leaving it dry. This will in my experience reduce the internal rusting issue.

 

[Lpgc]

The old stat is 160F. I can't check the new stat now it's fitted, I seem to remember it being stamped 70C (which is 158F) or a little cooler like maybe 65C (which is 149F).

The designs are almost identical but the old stat has a small triangular shaped cutout at the edge of the middle part that opens, the new stat doesn't have the cutout.

Hoping the high temp was just due to the old stat not opening, I suppose I'll find out when I next use the boat.

Been thinking about buying a new stat housing, there is rust in mine but the area the stat and O ring sit in seem relatively rust free and smooth. First time I fitted the new stat (and last and only time I refitted the old stat) I followed Michael Romer's advice (YouTube video) and used a bit of silicone sealer on the underside of stat and O ring, besides helping it seal I was concerned that the O ring didn't seam very secure in it's groove, didn't want it getting loose and making it's way around the engine/exhaust coolant channels or water pump. Other times I've had the new stat removed I didn't use silicon, it seemed cleaning bits of rust from the stat would be a regular job and the silicone slowed the job down. But I've refitted the new stat with silicone this time.

Been making thermostat housing gaskets from gasket paper and keep a few gaskets and tools on the boat.

Hopefully it's a bit early to be asking about winterisation but when it gets to the time I plan on draining water from the block and exhaust manifolds, remove engine belts, fill with glycol based antifreeze, attach an electric drill to the water pump and turn it to circulate/mix the antifreeze, fill the exhaust cooling channels with antifreeze, drain the raw water pump. Does this seem a good plan?

The only other work I've done on the boat recently is tidy loose wires under the dash, mosty the wires that come up from the floor (route to the engine bay) and go up to the dash. The fire extinguisher mount was on a loose carpeted small panel that had obviously once been fitted in the corner of the footwell under the helm hiding the wires. Seems the previous owner removed the panel when he fitted a 12" sub speaker in the footwell / bulkhead area between cabin and helm. He'd also relocated the helm fuse panel to a position that didn't leave room for the trim/fire extinguisher panel to be refitted. I put the fuse panel back to it's original position and refitted the trim/fire extinguisher panel which now hides the wiring and looks a lot neater. There's still a hole through the bulkhead where the speaker was fitted (I removed it months ago because I wanted rid of the speaker cab that protruded into the cuddy) but I can now refit the speaker to fill the hole, just not refit the cabinet.

Other work I'm planning on doing is to fit an ignition relay on the engine, wire it so the purple ignition on wire throws the relay, the relay will switch power from the circuit breaker on the engine to the coil. The VHF is noisy when the engine is running, I think it's being affected by a noisy power feed (from the helm) because the helm feed supplies the coil directly. If the helm doesn't need to supply the coil directly I could use the Amps saving on the helm feed to run a cooler in the cuddy without needing to run another feed from the battery selector switch and another ground wire.

 

[Lou C]

With the stats I always test them in a pot of hot water with an old style radiator thermometer before installing to make sure they open at the rated temp and far enough.
When installing I use some gasket sealer on the gasket & bolts but nothing on the o ring.
As far as winterizing what I do is run it a good 1/2 hr to 45 min on the water hose to flush out as much of the salt, calcium & rust flakes as possible. Then change the oil & filter. Next run it again to check for leaks & then fog it thru the carb. Let it cool off then open & poke all drains. Next I replace the drains & fill the engine with propylene glycol AF vis the big hose on the front of the engine. All I do is disconnect the bottom of that hose to drain then reconnect it and disconnect the top end at the stat housing. Next fill the engine with AF from the same hose till some AF spurts out of the stat housing & then reconnect the hose. Fill the manifolds the same way (via feed hoses). Lastly I fill the raw water intake hose from the transom with AF till it runs out the water intakes on the drive. This also pushes water out of the p/s cooler on the back of the engine. That’s all I have done for 22 years in salt water. If you have chronic running hot issues that may require de scaling the cooling passages with one of the commercially available solutions…