1996 Marine Power TBI fuel pump replacement FYI

[George L]

I Just replace all four fuel pumps on my motors.
Purchased the lower (low pressure units) from JEGS.com
These are standard Cater units and cost me $ 112.00 each.
The upper units (hight pressure) are standard GM and are also made by Cater.
They are listed all over the internet for $311.00 but you can order them at NAPA for $158.00 each.

Interestingly they all started failing around the same time.

[Almarktool]

George,
are you running with stock fuel tanks ?
I'm looking to add more fuel capacity to my boat was
wondering if you had done anything like that .

Mark

[George L]

Hi Mark, I haven't looked into.

George

[CrazyIslandMoFo]

Hi George,
How many hours did your MP's have ...

[George L]

The port was replaced at 1020hrs. Due to blown head gasket that cracked the block ( from previous owner). It was replaced once before at 600hrs.

The starboard is original and has close to 1100hrs on it.

I saw in a previous post that one of your motors burned more fuel than the other. Did you find out what it was?

My port motor burns 20gal more per fill up. It runs 20deg. cooler than the starboard (160F as opposed to 180F). I'm wondering if the computer is thinking it's still warming up and dumping more gas?

I like to cruise at 3800 to 4000 rpm.

[CrazyIslandMoFo]

George, my starbord burns 20-30 gal for entire fill, while port is the one running hotter as you say...I have been working on this problem, I have just found port will not come up to WOT, I try not to tach them out, but needed to test'em... My motors have 1250+ hrs, Presently,my port is tripping the 50 amp breaker and I am having to parallel from starboard to get her started. As she starts, port motor shoots to 3000 RPM and holds for a few moments...she holds nice temp while trolling, and will come right down after crusing. I will go after the thermostat next...

[George L]

I have the TBI repair and troubleshooting manual that I just started reading to perform some tests. This is what I know up to now:
The TBI computer has preset settings for certain RPMs, temperature readings and manifold pressure readings. In addition it's very voltage sensitive.
If the voltage drops below a certain level then it goes into a default setting until things get back to normal. This could be causing your high idle. I know when the alternator failed on the port, I had high idle issues. Also, I'm running single wire alternators that need to build magnetic field before they start charging so a little burp of the rpms is needed sometimes. I've replaced them on both motors with 140amp units ($160.00 each marine grade) that put out 80amps at idle. I also replaced the charging wire with#4 stranded back to the starter and ran a dedicated ground #4 back to the battery. Never had an issue with idle after that. I have read that if you disconnect the batteries, the computers reset and have to go through a learning curve. I’m going to investigate this as well. Interestingly the dock power got unplugged on the boat two days ago and I had to tap start. I noticed that the port motor would not WOT as well. I'm going to attack the issue this week. I think my port motor burns more fuel because I have a 160F thermostat in it. Sometimes the temp is a 150F. I think this is telling the computer to dump more fuel until it warms up. There are a number of other possibilities as well. I'll post what I find.