Odd Fuel pump related question!

[DullBoy]

Hello,

New to boating this summer! Been amazing!

I purchased my first boat last November from an employee. A brand new to me 1992 Bayliner Capri with a 4.3l 2bbl with a Alpha one Gen 2 outdrive for $600. I had a lot of work ahead of me. I Discovered the boat had been left through 2 winters with water in the block. I removed the engine from the boat and inspected the block inside and out. Lucked out, no cracks, replaced the exhaust manifolds and plugged the block. Cleaned out the engine compartment, inspected all the mechanics leading to the outdrive, placed engine back. Replaced the gimbal bearing, and bellows. Rebuilt the outdrive with all new 1.81:1 ratio gears. Impeller was in great shape on the outdrive so I cleaned and reinserted. Did some floor work and added a new Bimini top for the kids to escape the terrors of the sun!

When the boating season started we took it out on our first trip! ?Great success! I have filled the tank 7 times with 90 100% gasohol! Then there was our last voyage 2 weekends ago. We spent the entire day with no problems, did some tubing, cruising on the grand river out to lake Michigan, and just being plain lazy!
On our trip back I started to get all kinds of alarming gauge readings. My tach started getting sticky, my mph gauge quit working, my temp went from 155 to 185-190 range, my battery gauge was reading over 18volts, oil pressure was around 75. I backed off from 80% throttle to 60% keeping it at plane. I approached the last 300 yards of our trip and had to drop throttle for a no wake zone. That when the motor just shut off! I pulled the cover and the top exhaust manifolds were unusually hot.
I checked oil and the reset switch while I was under the engine cover. Everything was ok for the most part. Attempted to start the motor and it tried but failure. Lucky the boaters in Michigan have all been in this spot and one towed me to the docks.

I inspected the impeller again it was fine. Oil was full and in good shape. Oil pressure sending unit is functional. Starter and all wires leading from are intact. Fuel pump is functioning with jumpers.

I have not tested the alternator yet. Battery was good and hot when I hooked to charger/tester.

I have read (in these very forums!) That this style fuel loop electrical system uses the starter to prime the pump while turning over. Then as long as there is oil pressure it will continue to run the pump when started. When inspecting the oil pressure sending unit, it does not share a tee with any switches that would preform that action. Would the alternator share responsibility for running the pump when cranking? The wire on the fuel pump is purple/yellow. I Have a wire coming from the alternator sharing that wire. The wire on the oil pressure sending unit has that wire as well. I read the starter has something to do with that, but that's not the case here. I discovered another purple/yellow wire leading off the harness to a wire crimp, but the end was cut previously. It was not a fresh cut! I checked all fuses as well. everything looks great, other than the fact I cannot get the fuel pump to run for the life of me! Am I over looking something?

Sorry for the long post. Just wanted to cover all angles!

 

[alldodge]

Hello,

New to boating this summer! Been amazing!

I purchased my first boat last November from an employee. A brand new to me 1992 Bayliner Capri with a 4.3l 2bbl with a Alpha one Gen 2 outdrive for $600. I had a lot of work ahead of me. I Discovered the boat had been left through 2 winters with water in the block. I removed the engine from the boat and inspected the block inside and out. Lucked out, no cracks, replaced the exhaust manifolds and plugged the block. Cleaned out the engine compartment, inspected all the mechanics leading to the outdrive, placed engine back. Replaced the gimbal bearing, and bellows. Rebuilt the outdrive with all new 1.81:1 ratio gears. Impeller was in great shape on the outdrive so I cleaned and reinserted. :facepalm: Did some floor work and added a new Bimini top for the kids to escape the terrors of the sun!

When the boating season started we took it out on our first trip! ?Great success! I have filled the tank 7 times with 90 100% gasohol! Then there was our last voyage 2 weekends ago. We spent the entire day with no problems, did some tubing, cruising on the grand river out to lake Michigan, and just being plain lazy!
On our trip back I started to get all kinds of alarming gauge readings. My tach started getting sticky, my mph gauge quit working, my temp went from 155 to 185-190 range, my battery gauge was reading over 18volts, oil pressure was around 75. I backed off from 80% throttle to 60% keeping it at plane. I approached the last 300 yards of our trip and had to drop throttle for a no wake zone. That when the motor just shut off! I pulled the cover and the top exhaust manifolds were unusually hot.
I checked oil and the reset switch while I was under the engine cover. Everything was ok for the most part. Attempted to start the motor and it tried but failure. Lucky the boaters in Michigan have all been in this spot and one towed me to the docks.

I inspected the impeller again it was fine. Oil was full and in good shape. Oil pressure sending unit is functional. Starter and all wires leading from are intact. Fuel pump is functioning with jumpers.

I have not tested the alternator yet. Battery was good and hot when I hooked to charger/tester.

I have read (in these very forums!) That this style fuel loop electrical system uses the starter to prime the pump while turning over. Then as long as there is oil pressure it will continue to run the pump when started. When inspecting the oil pressure sending unit, it does not share a tee with any switches that would preform that action. Would the alternator share responsibility for running the pump when cranking?

No

The wire on the fuel pump is purple/yellow. I Have a wire coming from the alternator sharing that wire. The wire on the oil pressure sending unit has that wire as well. I read the starter has something to do with that, but that's not the case here. I discovered another purple/yellow wire leading off the harness to a wire crimp, but the end was cut previously. It was not a fresh cut! I checked all fuses as well. everything looks great, other than the fact I cannot get the fuel pump to run for the life of me! Am I over looking something?

Sorry for the long post. Just wanted to cover all angles!

:welcome: to iboats

All that work and did not replace a 2 year old impeller, :facepalm: but I'm getting off topic






Purple goes through the oil pressure switch (if you have one) and Purple/Yellow comes from the start circuit. You were running fine until all the gauges starting going. My guess is you have an electrical issue. Break out the volt meter and start checking connections. You have something loosing connection

 

[DullBoy]

Oil sending unit only. I did not find a switch anywhere. Sending unit is an older style shaped like a bell with only one wire attached to the top. Probed around with the meter, couldn't find any shorts. My voltage gauge on the boat works fine. Tested with a nine volt and it read correctly. Does the alternator have anything todo with this loop? It has the same color wire attached as the fuel pump. Let me rephrase that, is the voltage regulator somehow involved with that loop? I only ask this because this is an odd year setup for mercruiser and could not find answers no matter were I looked!

 

[DullBoy]

Oil sending unit only. I did not find a switch anywhere. Sending unit is an older style shaped like a bell with only one wire attached to the top. Probed around with the meter, couldn't find any shorts. My voltage gauge on the boat works fine. Tested with a nine volt and it read correctly. Does the alternator have anything todo with this loop? It has the same color wire attached as the fuel pump. Let me rephrase that, is the voltage regulator somehow involved with that loop? I only ask this because this is an odd year setup for mercruiser and could not find answers no matter were I looked!

 

[DullBoy]

Sry, on cell. Didn't mean to dbl post

 

[Fishermark]

With all the gauges acting up I too would suspect a bad connection. First place to try is the main engine harness plug. Disconnect it and see what condition the pins are in. Pretty much everything goes through that big plug.

 

[alldodge]

Oil sending unit only. I did not find a switch anywhere. Sending unit is an older style shaped like a bell with only one wire attached to the top. Probed around with the meter, couldn't find any shorts. My voltage gauge on the boat works fine. Tested with a nine volt and it read correctly. Does the alternator have anything todo with this loop? It has the same color wire attached as the fuel pump. Let me rephrase that, is the voltage regulator somehow involved with that loop? I only ask this because this is an odd year setup for mercruiser and could not find answers no matter were I looked!

Lets start with this, all purple wires on a Merc go hot when the key is turned to run. The ALT is also turned on when the key is turned. The ALT does not have a direct link with the fuel pump, but if the ALT is pulling more current then normal it can reduce voltage which in turn can cause other issues. Turn your key to run and check to see if your fuel pump is running. If pump is not running check for 12V at the pump. If it is running see if you have fuel going to the carb by moving the throttle forward and looking for fuel being squired in.

If you have fuel and it will not start need to check on the electrical side

 

[DullBoy]

OK first I jumpered the fuel pump to prime the carb. Boat started no problem. The fuel pump does not turn on with the key in the on position. I know that if the fuel pump runs with the boat off it will push fuel past the float. I hooked my meter to the hot side of the fuel pump and grounded to the black wire on the pump as well. I turned the key on, nothing, cranked the motor, still nothing. I checked the main harness plug an it was in great shape, almost like new. I cleaned both ends with contact cleaner from radio shack. Reinstalled harness repeated checks. Still no voltage.

I checked all the gauges. Had water in the speedometer line. This boat uses the outdrive style hook up for the speedometer not a pitot. I read these can be problematic. The rpm gauge seems gummed up, I ordered a replacement. Oil sending unit is sending correct signal to the pressure gauge. I apparently was getting a an overheating issue, the boat was loaded with guests and gear so I will replace the impeller as a precaution. boiled the thermostat, working correctly, opened up around 155-160.

Im back to the electrical issue. I will double check the harness all the way threw again to be 100% positive I don't have any shorts. I did loom a lot of the wiring b4 I put installed the motor over the winter.

The purple wire should be hot for the most part when the key is on? I'm pretty positive on it not being the fact, but I will continue to tear through it until I find the bug.

Remember this is a 2 barrel model. I have to be over looking something.

 

[alldodge]

OK first I jumpered the fuel pump to prime the carb. Boat started no problem. The fuel pump does not turn on with the key in the on position. I know that if the fuel pump runs with the boat off it will push fuel past the float. I hooked my meter to the hot side of the fuel pump and grounded to the black wire on the pump as well. I turned the key on, nothing, cranked the motor, still nothing. I checked the main harness plug an it was in great shape, almost like new. I cleaned both ends with contact cleaner from radio shack. Reinstalled harness repeated checks. Still no voltage.

I checked all the gauges. Had water in the speedometer line. This boat uses the outdrive style hook up for the speedometer not a pitot. I read these can be problematic. The rpm gauge seems gummed up, I ordered a replacement. Oil sending unit is sending correct signal to the pressure gauge. I apparently was getting a an overheating issue, the boat was loaded with guests and gear so I will replace the impeller as a precaution. boiled the thermostat, working correctly, opened up around 155-160.

Im back to the electrical issue. I will double check the harness all the way threw again to be 100% positive I don't have any shorts. I did loom a lot of the wiring b4 I put installed the motor over the winter.

The purple wire should be hot for the most part when the key is on? I'm pretty positive on it not being the fact, but I will continue to tear through it until I find the bug.

Remember this is a 2 barrel model. I have to be over looking something.

No power to the pump is the issue, just need to find out what caused the disconnect. Check for a blown fuse. What color is the wires on the pump?

And yes the purple wire should be hot when the key is turned on

 

[Bondo]

Hello,

New to boating this summer! Been amazing!

I purchased my first boat last November from an employee. A brand new to me 1992 Bayliner Capri with a 4.3l 2bbl with a Alpha one Gen 2 outdrive for $600. I had a lot of work ahead of me. I Discovered the boat had been left through 2 winters with water in the block. I removed the engine from the boat and inspected the block inside and out. Lucked out, no cracks, replaced the exhaust manifolds and plugged the block. Cleaned out the engine compartment, inspected all the mechanics leading to the outdrive, placed engine back. Replaced the gimbal bearing, and bellows. Rebuilt the outdrive with all new 1.81:1 ratio gears. Impeller was in great shape on the outdrive so I cleaned and reinserted. Did some floor work and added a new Bimini top for the kids to escape the terrors of the sun!

When the boating season started we took it out on our first trip! ?Great success! I have filled the tank 7 times with 90 100% gasohol! Then there was our last voyage 2 weekends ago. We spent the entire day with no problems, did some tubing, cruising on the grand river out to lake Michigan, and just being plain lazy!
On our trip back I started to get all kinds of alarming gauge readings. My tach started getting sticky, my mph gauge quit working, my temp went from 155 to 185-190 range, my battery gauge was reading over 18volts, oil pressure was around 75. I backed off from 80% throttle to 60% keeping it at plane. I approached the last 300 yards of our trip and had to drop throttle for a no wake zone. That when the motor just shut off! I pulled the cover and the top exhaust manifolds were unusually hot.
I checked oil and the reset switch while I was under the engine cover. Everything was ok for the most part. Attempted to start the motor and it tried but failure. Lucky the boaters in Michigan have all been in this spot and one towed me to the docks.

I inspected the impeller again it was fine. Oil was full and in good shape. Oil pressure sending unit is functional. Starter and all wires leading from are intact. Fuel pump is functioning with jumpers.

I have not tested the alternator yet. Battery was good and hot when I hooked to charger/tester.

I have read (in these very forums!) That this style fuel loop electrical system uses the starter to prime the pump while turning over. Then as long as there is oil pressure it will continue to run the pump when started. When inspecting the oil pressure sending unit, it does not share a tee with any switches that would preform that action. Would the alternator share responsibility for running the pump when cranking? The wire on the fuel pump is purple/yellow. I Have a wire coming from the alternator sharing that wire. The wire on the oil pressure sending unit has that wire as well. I read the starter has something to do with that, but that's not the case here. I discovered another purple/yellow wire leading off the harness to a wire crimp, but the end was cut previously. It was not a fresh cut! I checked all fuses as well. everything looks great, other than the fact I cannot get the fuel pump to run for the life of me! Am I over looking something?

Sorry for the long post. Just wanted to cover all angles!

Ayuh,.... Welcome Aboard,... In the circuit yer describin', the power comes from the tiny terminal on the Outboard-side of the starter's solenoid, durin' the crankin' to start the motor,...
I believe it's a pur/ yellow wire,...
When the motor starts, 'n ya release the key, power is supplied through the oil pressure Switch, which should be mounted way down low on the block, portside, 'bout mid-block,....
It should have a purple wire on 1 side, 'n the pur/ yellow beyond to the pump,...

Oil pressure Sender might be T'ed to it, or mounted next to the distributor,....

 

[DullBoy]

Thanks Bondo! I located the switch! What a classic compared to what I seen being sold online. I check the plug and it was shot! I replaced the plugs and boat started right up. I used a bulb grease on them to protect from future corrosion. Is that an ok solution to prevent future electrical failure? Is there anything I can do to protect my wiring from corrosion for future reference? Last of all. I replaced the car battery that was in here with a deep cell marine battery, is that an ok fit? Wow great job mates!

 

[Bondo]

Thanks Bondo! I located the switch! What a classic compared to what I seen being sold online. I check the plug and it was shot! I replaced the plugs and boat started right up. I used a bulb grease on them to protect from future corrosion. Is that an ok solution to prevent future electrical failure? Is there anything I can do to protect my wiring from corrosion for future reference? Last of all. I replaced the car battery that was in here with a deep cell marine battery, is that an ok fit? Wow great job mates!

Ayuh,.... You can see My comment on Grease,...... I've taken to sprayin' my electrical connections with Fluid Film to prevent corrosion,...

Plain ole Grease if I can't reach the Fluid Film can,...

 

[ktbarrentine]

A boat being used as you describe would be better served by having a marine starting battery versus deep cycle. As for your impeller, they can "look" fine, but can be "set" such that their output is degraded. As mentioned earlier, while you have it out, replace it....they are relatively cheap.:greedy_dollars: