Help identifying modifications made by previous owner

[Truchero]

Hi! I’m in the process of reconditioning a Pearson Renegade. The motor did not work when I got it. I rebuilt the carburetor and now it starts without any hesitation. I’m on the hard and I’ve limited running the motor to a single 5 gal bucket. Anyhow, the engine appears to have gone through various modifications. Could someone help me figure out what is what?

(Please forgive how dirty the engine looks, I’ve been fiberglassing and sanding the boat for three months and have just got to working on the engine)

1) the thermostat appears to have been removed and there is a bypass valve, am I correct? How would I use it?

2) there is an external fuel pump that runs when I turn the ignition. There appears to be a switch on the back of the engine. Presumably to turn off the pump in case the carbs overflow or something, correct??

3) I changed the coolant and looked at the anode, it looked fine. The heat exchanger was warm when I ran it, so I think it’s working. Does it look like it was properly installed.

4) any other mods that you see?

Thank you!!

[ronstory]

Well, your motor is unusual. You have a late model block with an early model head and cooling system. Plus, I believe you have won the "Most hose clamps on an A4" award.

You can get an idea of the options of motors combos by looking at https://moyermarine.com/faqemorlm/ and zoom in the the photos to on the right. Your cooling system is the bottom three photos for reference.

I'm not familiar with early models, so I'll let the more knowledgeable handle mods. However, regarding question 4, I have the same Monitor HX and looks correct to me.

[Marian Claire]

It looks as if you have a recirculating loop set up. This is different than a by-pass. It allows you to control the operating temp manually. You would not need a thermostat.
The hot coolant exits the manifold. If the valve is closed all the coolant will be forced to move forward and go thru the HX and be cooled before it runs back to the FW pump via the return line. If the valve is open some of the hot coolant is recirculated to the return line. This mixes uncooled and cooled coolant. By adjusting the valve you are changing the temperature of the coolant entering the A-4.

I run a recirculating loop on my early A-4 and like the control it gives me when traveling in different raw water temps.
Hope that makes sense.

Dan
S/V Marian Claire

[roadnsky]

2) there is an external fuel pump that runs when I turn the ignition. There appears to be a switch on the back of the engine. Presumably to turn off the pump in case the carbs overflow or something, correct??

We should first address item #2 (PIC #3)
That is a fire just itching to happen.

You'll need to ditch that whole setup and wire in a proper OPSS.
(sold HERE on our host site)
While we're discussing it, what kind of fuel pump do you have?
If you don't know, take a pic and we'll try to figure it out.

[Marian Claire]

Truchero. You may have a old style Dole T-stat housing in that mass of fittings coming off the manifold. This, https://moyermarine.com/product-category/thermostats/ may help you ID it. You have a mix of A-4 parts. Late block and starter. Early head.
Edit: More questions. What type of pump is used for the FW loop? Is it tucked aft of the RW pump on the starboard side?

Dan
S/V Marian Claire

[Truchero]

I believe you have won the "Most hose clamps on an A4" award.

I'd love to see the leaderboards, though I can't take much credit for it!

By adjusting the valve you are changing the temperature of the coolant entering the A-4.

Do you happen to know what temperature the A-4 should be running at? I'll do my own research on it regardless. Thank you!

We should first address item #2 (PIC #3)
That is a fire just itching to happen.

Agreed! In fact, prior to the carb rebuild the setup caused the stuck floats to overflow into the bilge. Regardless, this diagram that I have since found appears to show that the switch setup is "correct", but it doesn't make it right.

Sorry for the size of my pictures, I don't know how to resize them.



Here is a pic of the pump


Back of the switch, anyone know what that sensor does on the positive wire?

Edit: More questions. What type of pump is used for the FW loop? Is it tucked aft of the RW pump on the starboard side?

Yes, it is tucked aft of the RW pump on the starboard side.


Thank you all!! Sorry for the late response, I've been working on putting down some non-skid all weekend. Your responses help a ton, especially since it's a bit of a Frankenstein. Maybe I'll name it "Frankie" (no offense to anyone).

[roadnsky]

Back of the switch, anyone know what that sensor does on the positive wire?

THAT is in fact your OPSS. (Oil Pressure SAFETY Switch)
A Coastie requirement, BTW.

Evidently, the toggle "switch" is a bypass switch installed possibly to prime the fuel pump.
IF it were my vessel, I'd remove that old switch and replace both the OPSS and the wiring with new.
That is a very important fail point and what I see there doesn't inspire confidence.
Just sayin'

[Truchero]

Evidently, the toggle "switch" is a bypass switch installed possibly to prime the fuel pump.

and the plot thickens... I'll definitely take your advise and fix the issue. I'm so glad I decided to make this post. I hesitated because the engine runs on the turn of the key, but I couldn't figure out half the stuff. One of the previous owners evidently knew what they were doing, but that too can get you into trouble.

[Marian Claire]

"Do you happen to know what temperature the A-4 should be running at?"

Short answer is no. To cold can contribute to plugs fouling. To hot can speed up the process of salt clogging up the passageways. The Moyer T-stat is 150.
I tend to run 150 to 160 at cruising RPM. This gives me some room on the high side if I need to increase the RPM. It also gives me some time to detect any temperature increase caused by crud in the intake, RW strainer, or some other issue. AFAIK I have had no abnormal fouling of the plugs due to operating temp. Again, I do not use a T-stat.
Dan
S/V Marian Claire

[romantic comedy]

with the fresh water cooling, as you have, I run mine at 180 degrees steady. Occasionally it will rise up to 190 which is still fine. I use the original late model thermostat and it maintains temp.

That is quite the plumbing job!!

[Truchero]

with the fresh water cooling, as you have, I run mine at 180 degrees steady. Occasionally it will rise up to 190 which is still fine. I use the original late model thermostat and it maintains temp.

That is quite the plumbing job!!

Thank you! I'd love to take credit for the "immaculate" plumbing, but I can't. Like many of us like to do, I clean my hands and point the finger to one of the PO. With that said, I have to admit that the PO somehow made it work. They combined two different engines together, installed a FW system, there were plenty of old impellers, caps, points, and spark plugs on the boat indicating continuous tuneups. And after being sitting for probably years, the motor runs almost instantly (after a carb tuneup). So I'm not complaining too much, it could be worse.

[ronstory]

More Hose Clamps, Master?

[edwardc]

...
Do you happen to know what temperature the A-4 should be running at? I'll do my own research on it regardless. ...

Salt begins to crystalize out of seawater around 160 degrees F, so most raw water systems try and stay below that in order to reduce fouling of the cooling system.

Fresh water systems can run hotter, and most run around 180 deg F. The engine is happy at that temp, with slightly better fuel efficiency and slightly less plug fouling. The down side is that the higher temp ages things quicker in the engine compartment and adjacent lockers, and the extra heat ends up in the cabin at the end of a long motoring passage somewhere.

MMI used to include a blob of yellow 200 degree hot-melt on the block of their rebuilds in order to diagnose whether the engine had ever been above 200 degrees. This suggests that this is probably a good temp to always stay below.

Ours FWC system runs at 150 at idle, but comes up to 180 and stays there with any throttle applied. I'm happy with this arrangement. I run the engine at idle for several minutes until the temp comes down before shutting down. I also open the cockpit lockers for a while to help dump the engine heat outside the cabin.

[romantic comedy]

Thank you! I'd love to take credit for the "immaculate" plumbing, but I can't. Like many of us like to do, I clean my hands and point the finger to one of the PO. With that said, I have to admit that the PO somehow made it work. They combined two different engines together, installed a FW system, there were plenty of old impellers, caps, points, and spark plugs on the boat indicating continuous tuneups. And after being sitting for probably years, the motor runs almost instantly (after a carb tuneup). So I'm not complaining too much, it could be worse.

I think once you figure it out it will be fine. You will have to keep your eye on it when running and adjust it for best performance.