1999 BF130 Problem with WOT under load

Hi!


Bought a 20 foot boat in May with a 1999 BF130.
Previous owner claimed the boat runs at 38 knots (44 mph) WOT. Talking to owners with same boat and engine confirms this speed.


However, I soon discovered it did only 20 knots (23 mph). I changed the high pressure fuel filter (VST Upgraded to 2002) which was in horrible condition - all brown and "imploded" by the fuel pressure. This increased the WOT speed to 30 knots (34.5 mph) with optimal trim. Max RPM is approx 5200 under load. At neutral the engine can reach 6k, and previous owner claimed WOT under load should get close to 6k.


However, it seems like I'm still missing approx. 10 mph, and I feel the boat is lacking power - especially when heavy loaded.


I have done the following:
- Replaced inline fuel filter
- Cleaned inline water separator (no water found)
- Replaced low pressure fuel filter
- Drained water separator next to low pressure fuel filter
- Replaced high pressure fuel filter including o-ring (HORRIBLE condition)
- Replaced insulator/screen below high pressure fuel pump (good condition - not really neccessary)
- Replaced high pressure fuel pump (working condition, but were corroded and a probable cause of the horrible high pressure filter)
- Inspected VST tank (clean!)
- Replaced breather filter for VST.
- Changed thermostat (poor condition)
- Tested PCV for vacuum and "clicking" sound when placing finger at end. (Seemed OK.)
- Checked IAC screen. (OK condition)
- Inspected throttle body (OK condition)
- Inspected breather filter on silencer (not perfectly clean, but should be OK)
- Inspected throttle valve (goes full horizontal at WOT)
- Removed each injector connector and listened for idle speed change (change observed at each injector)
None of the items mentioned above as increase WOT speed.


Yesterday I measured the TP Sensor (only at the sensor connector as I dount have the test-harness to connect at ECM), and the output was 4.28V at WOT and 0.48V at idle. Voltage supplied is 4.97V. This is within spec, but only by 30mV at WOT. Could this be an issue? Sadly it doesn't seem to be possible to replace the TP Sensor - I have to change the complete throttle body! I need to be completely sure that this is causing the issues before buying a new one.


I have not measured the fuel consumption, but it seems quite high.


At heavy load I also experience quite a lot of oil film in the water surrounding the motor. However, I am not able to spot any obvious oil leaks inside the engine, and I am not able to see any oil dripping from the motor when fully tilted upwards.



I am no mechanic, and this is the first time I've ever fiddled with engine-repairs so please bear with me


Any help is appreciated!

It looks like you have done quite a lot of fixing and testing. Kudos to you for even finding the PCV. The 115/130 are the only Hondas that have one...most do not even know they are there.

A couple of other things that I did not see that you did....

Change spark plugs .....use only NGK ZFR7F. The good news is....they are pretty cheap.

Make sure you have good fresh fuel.

The above two items are critical to good running of that engine.

If you can, check the fuel pressure at idle and full throttle. You might have a fuel pressure regulator screen partially clogged (at the top of the fuel rail). You may have to loosen the fuel rail to get it off to inspect.

You said you changed the vst filter....did you check to be sure that the hose is free of obstructions? Can you blow through it.

Has there been any change to the propeller from the former owner to you? If not, is it in good shape. .

Has anyone changed the position of the engine?

As you can see, I am scraping the bottom of the barrel for suggestions.....

Speaking of scraping the bottom of the barrel.....how much buildup is there on the bottom of the boat? If there is much growth, that can really slow you down. Just had a customer complaint that his pontoon was only doing about 20 mph and could hardly get to 4500 rpm. Motor tested good. I took it out myself and he was correct. We cleaned the tubes and took it out again and got 5500 and 37 mph....just from cleaning the bottom.

You did not say, but I am assuming that the engine has no misses at high speed. As a side note, revving the engine while in neutral to 6000 rpm means nothing (not under load) and is not good for the engine.

As for the oil. First check the lower unit gear lube for water. If that looks good, then remove the starter and look inside the flywheel cavity. It should be bone dry. It is not unusual for oil to get into this area if water has gotten into it and corroded the core plugs or damaged the crank, thus damaging in the crank seal.

I probably have missed something...but there are a few things to check..

Mike

Hi Mike!

Thank you for the input!

Spark plugs:
Spark plugs have been changed to NGK ZFR7F this summer.

Fuel:
The boat was delivered with almost empty tank and I have filled it a couple of times since, so I assume the fuel is OK.

Fuel pressure:
Yes, i would like to check the fuel pressure, but I don't have the necessary equipment available.

Pressure regulator screen:
I have actually bought one of these tiny screens, but not changed it yet as the pressure regulator seemed to be a hazzle to remove. Will try to change it asap.

High pressure fuel filter - hose
Do you mean the hose connecting the high pressure fuel filter to the fuel rail? It looks good from the outside, but I could try to blow through it.

Propeller
The propeller is in good shape. It has recently been changed by the previous owner, but he said that he went to the shop with the old propeller and asked for a similar one, so I assume it is correct for the boat.

Engine position:
It has not been changed.

Buildup:
There's not much buildup. The hull was completely clean when I bought it.

No misses at high speed.

ONE REMARK:
Prior to buying the boat I took it to a Honda repair shop to change the timing belt and internal anodes. Can anything be done wrong in the process of changing the timing belt that could cause this problem?

Oil:
Thank you for the suggestions. I'll take the boat out of water next weekend for winter storage (short boat season in Norway!!) and then I'll check it.


Again, thank you for all the suggestions Mike. It is very much appreciated!


Trond

My reference to the VST filter was the filter for the VST vent. That is the filter that is located just above the VST and is in line with the vertical hose. That is the hose that should be clear of obstructions.

Your question on the timing is a good one. Timing will definitely affect performance. I did not bring it up since the compression was so good, but it would be good to check it. Even if it is off just one notch, that would slow it down.

Once you get the plastic cover off of the top, you align the "T" arrows on the cams with similar arrows on the lower timing belt cover (plastic under the cams). Then there is a small notch on the top edge of the crank pulley. It should align with an arrow on the lower timing belt cover (I think....on the port side of the engine). I always seem to have difficulty finding it....it is very small....I really need to get my eyes checked.

Now for the prop....another potential variable. Did the former owner trade the old prop in or did they keep it as a spare? If the new prop has a larger pitch, that could slow the boat down and lower the rpms. Theoretically...a larger pitch will make the boat go faster....but the engine has to be able to handle the load. If the engine does not have enough horsepower.....it slows down. If you do not have the old prop to compare it to, perhaps you can compare it to the prop used by the other people you talked to that had the same boat/motor combination.

Sorry that your boating season is so short. Hopefully, you will find a simple solution to your issue.

Let us know what you find.

Mike

Hi!

Propeller
The prop is original Honda 13x19 which should be OK for this boat. However, I'll check to see what others with similar boat/engine have.

Pressure regulator screen:
There was a bit of debris on this screen. See attached photo. I replaced it. This increased the top speed 1.6 knots (1.8 mph). Not much, but the top RPM also increased from 5100/5200 to 5300/5400. As there was quite some debris observed here, I assume there might be a problem with clogged injectors also??


VST Filter Hose
No obstructions. I could blow through the pipe.

TP Sensor
What about my measurements on the TP Sensor? At WOT the output is merely 0.03V above specified voltage criteria.