1992 Volvo Penta 230 with SPA-1 Overheating

sctbirdguy

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Jul 24, 2017
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I used to think I was smarter than average then I bought a boat, not any boat, but one that was known to overheat. How hard could it be to fix? I know nothing about boats…

So I have a 1992 Excel 18SX with a Volvo Penta 230 “Red Block” and a SPA-1 out drive.

Symptoms:
1. Idles all day at the lake just fine
2. Idles, revs runs perfect in the driveway dunked in a tub of water. Water level is just passed the intake holes.
3. Overheats on plane under load. Takes 20 mins or more to get hot. 230-ish? Temp gauge is not a precision piece of equipment. Temp immediately goes down after returning to idle.

Frustrations:
1. Oil is nice and clean and does not appear to have any water or coolant in it. It has been run a few hours while I have tested over the last month and the oil level stays consistent.
2. Antifreeze is clean and the level does not go up or down.
3. Antifreeze does not bubble while running.

What I have tried starting at the bottom working your way up:
1. Replaced the water neck and seal (removed the lower unit) + greased and tightened lower unit.
2. Checked and tightened the “S” hose, the exhaust bellows and the gimbal or PTO bellows.
3. Checked and tightened all clamps and bolts from the transom up to the sea water pump.
4. Replaced the sea water pump and all seals connecting the copper pipes to the brass pump housing.
5. Disassembled the heat exchanger replaced all seals and proved water flowed easily through the sea water core.
6. Replaced the exhaust manifold including the gaskets and the rubber gasket connecting the manifold to the exhaust down pipe and all copper pipe gaskets connecting to the manifold.
7. Replaced the thermostat.
8. Replaced the head gasket and inspected the heads and block visually as best I could. Looked clean and the surfaces appeared both flat, clean and crack free. (Used my very bestest steel drafting ruler!)
9. Replaced the inboard water pump.
10. Replaced the antifreeze, several times. Not by choice but who knew it would leak all over taking an engine apart!?!?
11. When replacing the head gasket I noticed the cam shaft and intermediate pulley alignment dots were not aligned so everything has been put together the correct way.
12. Timing has been set to 6 degrees BTDC at 850 RPM and timing does not exceed 36 degrees at 4000 RPM.
13. Dwell angle has been set to 62 degrees. (This seems like it will cook the coil, but what do I know).
14. For good measure I added permanent straps to the trailer and fixed all the old lighting, wiring plug etc. scotch locks should be illegal and anyone who uses them besides for an emergency fix should be publicly shamed. I do feel the trailer lights are not causing the boat to overheat though)

What am I missing? Maybe the pipe that runs from the water neck to water intake? It draws lots of water in the bucket though.

Could test for gas in antifreeze, need to rent that equipment.

Shot the motor with the IR and it didn’t appear to be that hot, however the engine had been idling for a few minutes also no water or antifreeze boils out of it but it goes back to what I would consider a normal temp after idle. And IR is susceptible to reflection and anomalies due to unqualified users such as me.

One odd thing is it really feels like the exhaust tube is filling with water and I am getting an exhaust restriction at high rpm under load. Also lots of water drains from the exhaust by-pass at the bottom of the transom near the sacrificial anode. I know water is supposed to come out there but lots does! Another strange thing is you can here glug glug from somewhere when turning off the boat…

I don’t can anyone help? Otherwise it might get a new home next to the Bismarck.

Thanks!
 

Scott Danforth

Grumpy old guy who plays with boats
Joined
Jul 23, 2011
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40,930
Never use a tub, always use muffs

You baked your impeller

Check your water hose connection on the drive. Known failure point
 

sctbirdguy

Cadet
Joined
Jul 24, 2017
Messages
6
Never use a tub, always use muffs

You baked your impeller

Check your water hose connection on the drive. Known failure point
How come you shouldn’t use a tub? I had the hose running in it the entire time and the water was cool to the touch. It’s probably 20 gallons of water. 90% of the heated water spilled from the transom and didn’t go back in the tub. However, I won’t do that again if that is a possibility.

I also had it on the muffs but I wanted to make sure the pump was pumping and not cheating with city water pressure. I should probably check the brass pump housing as well.

I have another impeller. I will swap it again.

I did inspect the copper pipe that connects to the transom and to the “S” that then connects to the water neck and it seemed fine but I should probably replace the “S” hose, and both bellows anyway. Is that the correct one you are talking about?

Thank you for the quick response and the ideas. I will give them a try.
 

Scott Danforth

Grumpy old guy who plays with boats
Joined
Jul 23, 2011
Messages
40,930
How come you shouldn’t use a tub?
because the raw water pump is at the crank centerline which is the top of the drive. you have to have water up that high or higher to get the pump to prime.

I also had it on the muffs but I wanted to make sure the pump was pumping and not cheating with city water pressure. I should probably check the brass pump housing as well.
your city water could be 150 psi and it still would not "cheat" anything the path to the motor is from the intake casting, up thru the swivel assembly, out the problematic fitting, thru the hose to the power steering cooler, up vertically thru the power steering cooler, then back down to the hose that zig-zags its way to the front of the motor to the F5B raw water pump

replace this fitting.
https://i.ebayimg.com/images/g/3FUAAOSwBDRhMJog/s-l500.jpg
 

sctbirdguy

Cadet
Joined
Jul 24, 2017
Messages
6
The raw water pump is attached to the engine above the crank and sucks water up through the lower unit directly through the screen and into the heat exchanger. I don’t think it is ever below the theoretical water line, for sure not on plane Anyway doesn’t matter. Won’t do that again!

I just thought the city water pressure might push water up to the impeller which would then not show if I had a leak at the fitting you described. My water pressure is in the low 70’s….lol I measured that too!

Long story short I have replaced that fitting. I called it the water neck. I probably made that name up after some beer and frustration venting.

I appreciate the follow up!

You don’t want to buy a boat do you? :)
Slightly used by an older couple for going to church and the grocery store on sundays and that’s it.

I am so frustrated. I feel like the Johnny Cash song “One piece at a time”. I am going to have a brand new 1992 boat that cost $30,000 worth $3,000. They were only $10k brand new….ugh.

Might have to magnaflux the block and head….

Thanks again.
 

Scott Danforth

Grumpy old guy who plays with boats
Joined
Jul 23, 2011
Messages
40,930
remember, overheat is a lack of cooling water flow

could be the glycol side, could be the raw water side

measure the pump output. if the pump is bad, spend the $150 on a new pump

if you ever lost an impeller blade, look for it.
 

sctbirdguy

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Joined
Jul 24, 2017
Messages
6
remember, overheat is a lack of cooling water flow

could be the glycol side, could be the raw water side

measure the pump output. if the pump is bad, spend the $150 on a new pump

if you ever lost an impeller blade, look for it.
Agreed on the water flow. Replaced both pumps already. I am stuck on the exhaust. I really think at high rpm the raw water can’t get out. To be fair I don’t understand how the exhaust bypass and exhaust tube work. Unfortunately, I will have to pull the engine and the lower unit again to learn. Plus buy those parts!

On the bright side I am fairly certain in a few more months I will know more than the entire 1992 Volvo engineering staff about this engine / out drive combo.
 

sctbirdguy

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Joined
Jul 24, 2017
Messages
6
The drive was originally designed in the early 80s along with the motor
Well the engine is from the 70’s. Don’t know about the outdrive. Their seatbelts are wonderful I suppose.

I do understand this is supposed to be a pretty rugged setup. IDK…They run hot from the factory which doesn’t leave much head room for small problems.
 

QBhoy

Admiral
Joined
Mar 10, 2016
Messages
6,575
Have you the internal cooling thermostat in it ? Different from the raw water cooled by about 20 degrees im sure.
Apart from that. Check your coolant tank cap seal and function. If these are faulty they release pressure before they should and the pressure of the coolant system reduces to atmospheric. Obviously then it can’t function as it would under pressure.
 

sctbirdguy

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Joined
Jul 24, 2017
Messages
6
Have you the internal cooling thermostat in it ? Different from the raw water cooled by about 20 degrees im sure.
Apart from that. Check your coolant tank cap seal and function. If these are faulty they release pressure before they should and the pressure of the coolant system reduces to atmospheric. Obviously then it can’t function as it would under pressure.
Swapped the thermostat.

I haven’t swapped the heat exchanger cap yet. It does release pressure, even days after running, when opened. It doesn’t boil over, but maybe I will get a new cap.

Thanks!
 

QBhoy

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Joined
Mar 10, 2016
Messages
6,575
Swapped the thermostat.

I haven’t swapped the heat exchanger cap yet. It does release pressure, even days after running, when opened. It doesn’t boil over, but maybe I will get a new cap.

Thanks!
Ok. So the cap is either doing it’s job and releasing pressure because of another issue, or it’s what’s at fault. If the cap replacement doesn’t work. Then it’s likely a cylinder head issue to be the favourite, if a couple of other reasons. I’d do a gas test if that’s the case, like you mentioned earlier.
 
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