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Mercruiser with Volvo accessories hard to start.

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Bluecollerboater

Contributing Member
I apologize if this is long winded. I have a 1995 carver 250 express that is new to me. It originally came with a Volvo penta 5.7 Gi and a duoprop. It now has a rebuilt 1987 Mercruiser 260. All the accessories from the Volvo were used on the new engine. So when I started it today I had to put it in neutral and pump it to get it started. I know it has some sort of fuel injection. I thought if it was fuel injected you did not have to pump it. Also when I did get it running it ran well but if I shut it down or it stalled it was hard to restart(more pumping the throttle to get it going. I know it has two volvo fuel pumps one just above the Volvo fuel filter and one back beside the distributor. Does this sound like a fuel pump problem or injection problem or something else. I have changed the oil and plugs cleaned the contacts on the distributor which were pretty clean to begin with And have a new fuel filter and a separate tank with fresh gas.thanks in advance for any help.
 
Perhaps a few photos of your engine would be helpful.

Bluecollerboater said:
I apologize if this is long winded. I have a 1995 carver 250 express that is new to me. It originally came with a Volvo penta 5.7 Gi and a duoprop. It now has a rebuilt 1987 Mercruiser 260. All the accessories from the Volvo were used on the new engine.

So when I started it today I had to put it in neutral and pump it to get it started. I know it has some sort of fuel injection.
Most likely TBI (throttle body injection)


I thought if it was fuel injected you did not have to pump it.
Correct.... there is no accellerator pump with fuel injection. Pumping the throttle lever will do zero.

Also when I did get it running it ran well but if I shut it down or it stalled it was hard to restart (more pumping the throttle to get it going.

I know it has two volvo fuel pumps one just above the Volvo fuel filter and one back beside the distributor.
This would be a higher pressure fuel pump for FI, and possibly a fuel cooler.


Does this sound like a fuel pump problem or injection problem or something else.
Have the fuel pressure tested, make sure that the low oil pressure fuel pump power interrupt is working along with start-by-pass system.
(the "start-by-pass" circuit momentarily powers the fuel pump until oil pressure is acheived and the N/O switch closes)

I have changed the oil and plugs cleaned the contacts on the distributor which were pretty clean to begin with
Cap/rotor contacts? Or contact points?
If contact points, is this perhaps the old Merc 260 ignition system?


And have a new fuel filter and a separate tank with fresh gas.
I usually suggest that we go through the main fuel tank system before resorting to a separate fuel tank supply.
There's not too much that can go wrong that can't be corrected easily.
Pull the fuel tank pick-up tube, clear the screen, check the 90* fitting, check/replace the anti-siphon valve, verify that the vent fitting and vent hose are clear, check the chemical condition of the fuel, etc.
I'd do this, and I'd not waste my time with the other fuel tank supply. We need to resolve the main fuel tank issue anyway.
Click to expand...

I read on another forum where you said that the 75 gallons of fuel is 3 years old.
If this fuel cycled through a few summer warm spells, it may be bad by now.
Pull off a sample, and test it.

Also, you said that the TBI engine was winterized.
If the TBI was fogged using the conventional carbureted engine method, the air sensing ports may be contaminated.
Most mechanics would not be using this technique. (rather than "fogging", an oil enriched fuel mixture is brought into the fuel system)


BTW, a 1995 boat would not be OEM equipped with a 290 drive..... more likely a DP-C or DP-C1 drive. Much better than the 290.

I also noticed this: "I just did the timing it is 8 degrees at idle (600 to 650 rpm) and 32 degrees at 4200 rpm."
You may want to look up your OEM ignition curve, and study it.
Ignition advance is much more critical for the Marine Engine.
The 32* @ 4.2k rpm is OK......., but I'd be more concerned with what the advance is @ 3.2k rpm.

The tension value of rusty flyweight return springs may be compromised. If compromised, they may allow the advance to come up too early and too strong.

.
 
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When I said I cleaned the contacts I meant the contacts on the distributor cap it is a electronic ignition.

The timing I did was on my last boat with a Volvo AQ260A and 280 outdrive. With the exception of the electro mechanical lift and reverse lock out I loved this set up. By the way you were spot on. I found the advanced weights rusted in place and one of the advanced springs was broken. I free'd up the weights and replaced the springs and the engine ran great. It took a while to find out the weights were the problem and even longer to find new springs.

The fuel in the main tank is 3 years old I am going to get rid of it I just have not had a chance yet.That is why I am using an auxiliary tank.

I was told by the previous owner that it was professionally winterized. I do not know if that is true or not. So I do not know if it was fogged the old way or if a gas oil mixture was introduced.

The 290 came from a sticker on top of the plastic black cover over the flame arrestor that says 5.7 Gi. There was a sticker on it that read:
transom assembly
Tsk. DP-S (290)
4111522228
3868299
with your help in another post we figured I probably have an SP-C.

Can I test the fuel pressure,low oil power interrupt and start bypass myself? If so how?
How do I check the air sensing ports?

thanks in advance everyone for your help, especially Ricardo Marine.
 
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Back to you....................

Bluecollerboater said:
When I said I cleaned the contacts I meant the contacts on the distributor cap it is a electronic ignition.
Ah.....


By the way you were spot on. I found the advanced weights rusted in place and one of the advanced springs was broken. I free'd up the weightsand replaced the springsand the engine ran great. It took a while to find out the weights were the problem and even longer to find new springs.
IMO, this is very risky without the aid of a Sun, King or Allen distributor machine.
The spring value must cause the flyweights to advance as per OEM specs.
A 2 or 3 degree error at the distributor, is a 4 or 6 degree error at the crankshaft.
All ignition advance specs are ultimately based on crankshaft degrees. When/if we were to see distributor degrees listed, the math must be done in order to calculate crankshaft angle.

NOTE: Ignition advance that comes on too early, or too agressively per RPM, can cause detonation.
Short of no oil pressure, or over-heating...... Detonation can become one of the most damaging concerns for a gasoline marine engine.


The fuel in the main tank is 3 years old I am going to get rid of it I just have not had a chance yet.That is why I am using an auxiliary tank.
I see!

I was told by the previous owner that it was professionally winterized. I do not know if that is true or not. So I do not know if it was fogged the old way or if a gas oil mixture was introduced.
Understood.

The 290 came from a sticker on top of the plastic black cover over the flame arrestor that says 5.7 Gi. There was a sticker on it that read:
transom assembly Tsk. DP-S (290)41115222283868299
with your help in another post we figured I probably have an SP-C.
Most likely.

Can I test the fuel pressure, low oil power interrupt and start bypass myself? If so how?
Disconnect the wire from the "S" terminal at the starter motor and tape it off.
Turn the ignition key to the "Start" position, and see if you can hear the fuel pump operating.
If not, test for power at the fuel pump relay.

Or better yet..... see the Volvo Penta service manual section on trouble-shooting fuel delivery issues.

How do I check the air sensing ports?
Wow.... this would get deep into the trouble-shooting procedures.
I'd do your other items first, and see if you can get the engine to run.
Click to expand...
 
I know the springs with the correct spec are very important. I did a lot of research before I bought them and had to order them from a speed shop in ohio. I sold that boat to a friend and it is still running very well today.

When I have previously started the engine with the fuel issue I have heard the fuel pump activate so I think it is working.

I would love to check the manual but the only thing I know about the fuel system is it came off of a volvo 5.7 Gi(the reason I know this is because I still have the black plastic cover over the flame arrestor.I am pretty sure they had multiple versions of this engine there is no way to tell which one the boat had originally from the black plastic cover I still Have. The new engine is a 1987 mercruiser mie 260 with the fuel system, water pump and alternator from the volvo.
 
Bluecollerboater said:
When I have previously started the engine with the fuel issue I have heard the fuel pump activate so I think it is working.
Click to expand...
During normal operation, the electric fuel pump does not receive current until the engine oil pressure exceeds the N/O low oil pressure switch value, at which time the switch contacts will close.
Once the contacts are closed, the fuel pump relay is triggered..... and the pump operates.

However, during start-up (prior to oil pressure), there will be a "start-by-pass" circuit that powers the fuel pump relay.
During this, I don't know how you would be able to hear the fuel pump operate while the engine is running.

This is why I suggested removing the starter motor solenoid "S" terminal wire, and going into key switch "start mode".


.
 
Ok. I finally got a chance to get on the boat. The starter solenoid has the main red power wire a green braided cloth wire from the starter and a yellow wire from the knock sensor. Which one is the s terminal I should remove to check the "start by pass"? By the way my knock sensor looks pretty old and rusty could this have something to do with the hard starting?
 
Depending on the year model, most Merc or Volvo Penta solenoid energizing circuits are yellow, or yellow w/ red stripe.
This will be a small lead that will connect to the solenoid terminal marked "S".


Example photos only.

This is a HTGR/PMGR motor.

See the yellow w/ red stripe wire. This powers the "S" terminal from the key switch while in "start mode".

Note the other vacant small terminal...... this is what I suspect to be the "I" or "R" terminal.
Your starter motor may or may not have this terminal.

Note that the field wire has been disconnected from the output contacts of the solenoid in this photo.... not my photo, so I can't explain why.
(disconnecting this would be an option for you also)




Here's where it can get tricky..... but first just to clarify why you'll be doing this.

With the starter motor operating, it will be difficult to hear if the fuel pump is operating over the top of the starter motor noise.
By disconnecting the starter motor "S" terminal, we're prevneting the motor from having it's field energized.... IOW, quiet!

First you'll need to determine how the fuel pump relay is receiving power from the "S" circuit.
If it's receiving power from the other small terminal (the "I" or "R" terminal) then I believe that you could disconnect the "S" terminal wire, and energize the "I" or "R" terminal wire and see if the fuel pump relay energizes the fuel pump.


I just helped a cyber friend with something very similar. His yellow/red stripe wire did not make a direct "S" terminal solenoid connection.
Instead, it powered a five pin relay first, and then went on to the "S" terminal.
So you may want to trace this out.




Here's an old Delco Non-Gear reduction starter motor.




.
 
Thank you Ricardo,
mine is like the first pic. Except my field wire is green. There are only three wires. The field wire, a heavy red power wire and the yellow wire with red stripe that goes to a knock sensor. The knock sensor looks pretty old and rusty. Would this have anything to do with the hard starting?
 
I tried uploading pics before this site would not let me. I will try again. Today. What I know. The block is a 1987 mercruiser mie 260 hp. All the accessories are from a 1995 volvo 5.7 GIPMDA. It has the low and high pressure fuel pumps and a gm tbi. Alternator, starter, water pump all volvo. The distributor and coil are also volvo. All from the original 5.7 GIPMDA.
 
OK... that helps quite a bit.

Go here, and see if you can find the electrical schematic for the fuel pump system for the 5.7 GIPMDA.

It looks like this is TBI (throttle body injection).
TBI requires full fuel pressure in order to work.

There will be a N/O low oil pressure switch in the system.
You could momentarily and temporarily by-pass this switch, and see if the pump will operate.


Side note:
The list shows two types of installations for the 5.7GLPMDA.
One is for the Gimbal system drive, and the other is for the main suspension fork/pivot tube geometry drive system.

If you have this style, be sure to replace the bearing shown as SEQ #4.

If you have this style, be sure to do the annual engine drive coupler alignment procedure.



.
 
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Ok I took the yellow wire off the starter solenoid and turned the key. I heard the fuel pump come on initially for about 3-5 seconds to prime. Then I turned the key to start I got a relay clicking the big one in front of the starboard side manifold where the red resets are. But the fuel pump was silent after the initial 3-5 second prime. I then hooked the yellow wire back to the starter solenoid and started the engine. The engine started as soon as oil pressure came up. So I think Ricardo was spot on in the "start by pass" theory. What do I check now?
 
I took the fuel pump relays out and cleaned the terminals. After that I got the engine to fire on the first turn of the key twice only. Then it went back to starting only once the oil pressure came up. I am assuming this means I have a bad relay or two. That's another question I have a 5.7 gipmda the book exploded diagram only shows one relay I have two next to the low pressure pump.
 
Ok finally figured it out. I was testing the sockets for the fuel pump relay and everything was ok. I had already bought a new relay in case or to keep as a spare. So I put it in and nothing changed. The fuel injector relay directly next to it was the same relay so I tried popping it in there. Bingo. My motor now starts within seconds. Thanks to anyone who replied. Especially Ricardo for all your help. Now to post a new thread with the latest issue.
 
Ok i thought i fixed it, I was wrong. I would like to backtrack a little. When I disconnected the yellow wire with red tracer from the starter then put the key on engine not running the fuel pump ran for the initial 2 second prime. When i turned the key to crank the starter I heard a click from the starter relay but the pump did not run. What should I try now? The boat will still start once the oil pressure comes up but if this keeps up I will fry my starter. What would cause the fuel pump not to run while cranking?
 
Bluecollerboater said:
What would cause the fuel pump not to run while cranking?
Click to expand...
The start-by-pass circuit may not be functioning.
You'll want to test for fuel pump power/current while cranking.
This means both sides....... for the actual By-Pass circuit and for fuel pump relay power.

And if you want to, you could actually disconnect the field wire to the starter motor to eliminate it from operating while you do the testing.
 
Bluecollerboater said:
Where is the start by pass circuit?
Click to expand...
I don't know your system completely.
Typically a Start-by-pass circuit will begin at the starter motor solenoid, either at an "R" or "I" terminal.

This becomes energized during starter motor action.... and lets go immediately upon starter motor disengagement.
Meanwhile, the low oil pressure switch continues the fuel pump relay operation once above XX psi.
 
If you can get to it easily..... try disconnecting the field circuit at the motor itself.
This will allow you to simulate starter motor action w/out the noise interference.


This is an old Delco style.
The field circuit is actually a copper sleeve that comes from the lower solenoid terminal.



Here's a HTGR/PMGR motor.
These use an insulated braded copper conductor.

 
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