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BF115 Fuel injectors

C

Chris061

Member
Been awhile since I posted here as motor has been performing to my expectations. We only use the boat about 25 hrs each season so not alot of use.

2001 BF115 with updated VST,etc.. fuel always treated with Stabil marine and Quiklean, and I stick to the factory manual maintenance schedule for items like fuel filters, spark plugs, impellor kit, etc...

This year the motor is a bit erratic during start and idle. When cold it will start run 2-3 seconds and quit, next attempt it will stay running and idle but needs to warm up a few minutes before engaging prop, otherwise it will quit, plus during idle it seems to be missing but not throwing any codes.

I cleaned the IAC and installed with new O-rings, checked the Pcv it was good, and cleaned the ThrottleBody and checked the air elements they looked clean. Also pulled and tested T-stat, it is good.

Put back together and ran in test tank till warmed up and tested at higher rpm without prop installed, motor seemed to accelerate fine.
During warm up at idle I detected a slight miss, but at higher rpm it goes away. After consulting the T-shoot guide in factory manual, I tested the injectors OHM rating, using digital meter.
Manual shows 11.1-12.3 ohms as good. My injectors measured between 13.8 - 14.3, so way out of spec.

So, replacement injectors and seals will be ordered. I know I need to remove fuel rail, so will get extra O-rings for supply connection.
Anything else I should consider replacing while doing this job.
 
Hi Chris,

I have no experience working on the 115 nor any Honda outboard with fuel injection..My background with FI is automotive and diesel truck related so keep that in mind while reading my post.
The systems, for the most part, are very similar however.

While I wouldn't argue with a new set of injectors for these symptoms....they are getting on in years and will undoubtedly have some deposits....
....I'm just not sure I would condemn them for having a 1-2ohm difference from the specification.

Resistance can be subject to meter, test leads, connections and, most importantly sometimes, temperature differences.
I would be interested to know how the new ones compare though if you want to share.

Referencing the parts page linked below:

I take it you cleaned/inspected item 23. I would also suggest cleaning the tip of the intake air temp sensor and replacing it's oring...item 34.

You may also want to inspect/clean the fuel rail filter screen...item 5. I believe that would involve unbolting the fuel pressure regulator so you will want a new oring on hand for that...item 10.

While doing that, check the regulator vacuum line...item 37... for any signs of fuel getting past the regulator diaphragm.


It sounds like you do a VERY good job of maintaining your outboard. I hope my comments are helpful.

Good luck.
 
Hi Jgmo,

regarding the injectors.. I used a couple of different Fluke meters and got similar readings so I believe test is accurate.
I did a retest of them cold and they spec between 13 - 13.3. I agree they are close to spec.
Plus the expense of 4 injectors is pricey :(

Yes cleaned the IAC screen item 23 thoroughly. IAC ohm test is within spec.
I have not inspected / cleaned the IAT, will have to get O-ring before doing so. IAT ohm test is also within spec.

The fuel rail screen / O-ring at the fuel regulator were replaced 2 yrs ago along with ALL internal fuel lines.
So that item should be good.

Question for the members... has anyone Ohm tested a new injector? If so, what did it read?
Injector in question is part # 16406-zw5-000.

Thanks
 
Since you have a miss at idle, have you replaced the spark plugs to rule them out?
Also being a 2001 model, there is the possibility the cylinder head maybe cracked as they are known for, or has it already been renewed?
And being a 23 year old outboard, if it's been used in salt water, there is a good chance it may have a leaky cyl head gasket/corroded head, allowing water into the cylinders & causing a missfire. You could check this with a borescope & look for rust on the cylinder walls.

Bob
 
I agree on checking/changing the plugs, do they all look the same when you remove them?

Have you done the valve adjustment lately?

How do you use this outboard for the 25 hours per year ? A lot of low speed hours?
 
The boat is used on fresh water only, medium speed cruise with occassional high speed run, no trolling.
Valves were checked and adjusted along with new plugs this spring. Plugs all look similiar.
I removed / cleaned the IAT, it had a light coating of carbon like material on it. Did a test tank run and it seems better.
Will try a run on lake and report back.
 
Update...
Had the opportunity to send the injectors for cleaning / testing using an ANSU machine.
Report did not show any glaring issues, motor seems to run a bit better at start but after running at high speed on lake and but while at idle is a bit worse. Narrowed it down to cyl 2, performed a compression & leak down test, cyl 2 has a problem.
It may be just a head gasket or the often mentioned crack. Since the motor is over 20 yrs old, and repair will not be cheap (even DIY), have decided to get a new motor. If anyone needs a Bf115 for parts let me know.
 
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