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Honda 90 4 stroke high pressure fuel pump

J

jopl00

New member
I bought my father In law's Boston Whaler with a Honda 90 4 stroke last year. I left it with a Dealer to winterize, store and do a tune up because the Honda had a little hesitation on acceleration. On our summer vacation it ran great but after 30 minutes it started sputtering and would not run at high speed. I checked all fuel lines for leaks and pumped the fuel bulb. Pumping the fuel bulb helped a bit but the motor did not run above 4000 rpm. I foolishly forgot to check the air vent on the gas tank. I have never closed it. The Dealer must have closed it. I needed a wrench to open it. After that the motor would run for 5-10 at top speed 7000 rpm but then drop back to 4000 rpm max. The Dealer said that the high pressure fuel pump was the issue. I can imagine replacing the high pressure fuel pump is expensive. I didnt run the motor more than an hour or so eith the vent closed. It seemed to be running better after I opened the vent. I'm wondering if the fuel pump is damaged or just stressed? Will it fail? Should it just be replaced?
 
Hi,

I have a couple of questions for you:

Have you checked your fuel for contaminates... ie:water?

Have you cleaned, emptied, serviced the water separator?

Leaving the fuel tank vent always open invites trouble. Just a few minutes sitting in the rain can result in a large amount of water entering the tank. Also, over time, especially in moist climates, leaving the vent open can result in a surprising amount of water due to condensation.

I mention this because water in the gas can contribute to pump failure as well as poor performance.

I don't think I've ever had to use a wrench to open a tank vent. The guy that closed it must have bionic finger muscles!

What did the dealer base that "bad pump" information on? Did they attach a mechanical gauge and record low fuel pressure? Did they give you a copy of the results of the test? If not, it's not a valid diagnosis.

If the pump isn't putting out enough MEASURABLE pressure, then it is failing and will need to be replaced. It's as simple as that. I don't have the pressure specification otherwise I would share it with you.

Yes, the pump is expensive (around $375) and trying to get by with an aftermarket pump to replace it for cost savings might not work in your favor. Most aftermarket pumps are junk right out of the box. I'm sure there are exceptions but I couldn't tell you how to source one with any confidence.

You have to consider the cost and inconvenience....even peril....of having it fail on the water and stranding you as well as possibly costing you a tow bill to be rescued. If you can see it in that light, it eases the pain a little bit.

The service manual is well worth having if you decide to do the work yourself and save a bunch of money. I couldn't own a boat if I didn't do my own repairs because I simply can't (and won't) pay a shop. Besides, when finished, I will know the job was done correctly or, at the very least, who I need to talk to if it isn't. Not always the case with MANY shops these days.

Sorry you're having troubles.
 
jgmo said:
Hi,

I have a couple of questions for you:

Have you checked your fuel for contaminates... ie:water?

Have you cleaned, emptied, serviced the water separator?

Leaving the fuel tank vent always open invites trouble. Just a few minutes sitting in the rain can result in a large amount of water entering the tank. Also, over time, especially in moist climates, leaving the vent open can result in a surprising amount of water due to condensation.

I mention this because water in the gas can contribute to pump failure as well as poor performance.

I don't think I've ever had to use a wrench to open a tank vent. The guy that closed it must have bionic finger muscles!

What did the dealer base that "bad pump" information on? Did they attach a mechanical gauge and record low fuel pressure? Did they give you a copy of the results of the test? If not, it's not a valid diagnosis.

If the pump isn't putting out enough MEASURABLE pressure, then it is failing and will need to be replaced. It's as simple as that. I don't have the pressure specification otherwise I would share it with you.

Yes, the pump is expensive (around $375) and trying to get by with an aftermarket pump to replace it for cost savings might not work in your favor. Most aftermarket pumps are junk right out of the box. I'm sure there are exceptions but I couldn't tell you how to source one with any confidence.

You have to consider the cost and inconvenience....even peril....of having it fail on the water and stranding you as well as possibly costing you a tow bill to be rescued. If you can see it in that light, it eases the pain a little bit.

The service manual is well worth having if you decide to do the work yourself and save a bunch of money. I couldn't own a boat if I didn't do my own repairs because I simply can't (and won't) pay a shop. Besides, when finished, I will know the job was done correctly or, at the very least, who I need to talk to if it isn't. Not always the case with MANY shops these days.

Sorry you're having troubles.
Click to expand...
Thank you for your thoughtful response! You sound like someone alot like me but more knowledgeable about boats. This is only the second boat I have owned but I've been around them since I was 7. I'm now 75.
The Honda 90 runs well with no trouble at 7000rpm for about 10 minutes. Then it runs well but won't go beyond 4000rpm. That description is the symptom that the Dealer used to diagnose high pressure fuel pump. I understand that checking the fuel line pressure is one diagnostic but if the motor runs well for 10 minutes can I run a pressure test that will run 10 minutes? I think your comment about the motor failing on the Lake is my biggest worry. I use the boat to take my Grandkids for a ride. I think I will find a reasonable qualified Outboard Mechanic to just replace it and rest at night! Thank you again!
Joe
 
Hi Joe,
Well, I hope that's actually the problem.
Yes, once it's determined where to tap into the system and connect a pressure gauge (that's why having the manual is so helpful) you can drive it all you want with the gauge attached.
Hopefully your newfound tech will be able to do that for you.
Good luck and please let us know how it turns out.
 
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