Honda2006 BF 150 hp

I have a 2006 BF 150 that idles rough. The engine rocks or shakes at idle. If I throttle up in neutral to 1500 rpms the engine starts to surge...drop rpms then back up and back down. I was told it may be a vacuum problem. Anybody have any suggestions?

Re: Honda BF150

It appears no one is answering so here goes...


There are any number of things that it can be. The most basic are:

-Bad fuel/water in fuel - drain vapor separator into glass and check fuel.
-Bad spark plug - change plugs
-Vacuum leak - Make a visual inspection of all of the hoses. Check for kinks or leaks. Use a short hose up to your ear to isolate hissing sounds. Loose IAC valve, loose throttle body, loose intake manifold, damaged fuel injector seal, loose injector base.
-Low/ high pressure fuel pressure too low.
-Bad cylinder - do a compression test

I am not even addressing any potential sensor issues. Without an HDS, it could be a wild goose chase.

You did not say if this happened all of a sudden or slowly over time. If is was suddenly, look for something physical.

If this motor has been sitting and the fuel was not stabilized and vapor separator drained, then it could be a clogged injector, or clogged vapor separator. Missing one one cylinder.

Hopefully, you find something obvious. Without a manual, it is practically impossible to find anything other than the basic of problems.

Mike

Re: Honda BF150

Thanks Mike. It has slowly gotten worse during last summer. I changed the plugs, drained the VST and replaced all the filters. Tightened the IAC valve, I read in my shop manual that in setting the idle speed you should disconnect the IAC valve while running...I did and the engine died.

I pulled all the plugs and it seemed to me that one cylinder did not seem to effect the way the engine ran as much as the others.

The engine runs good for about 10 seconds and then starts running rough. Turn it off when it starts running rough, start it back up and it runs good again for about 10 seconds. If I trottle it up it starts to surge, throttle down and it runs smooth again for about 10 seconds.

Re: Honda BF150

To adjust the idle, you have to have a Service Connector (070PZ-ZY30100) plugged in to put the engine in service mode. Just disconnecting the iac will do as you have found...kill the engine.

The Service Connector can also help you read any codes you may have on the red "check engine" light by the number of blinks.

Here are the basics that should be done to get a base line...

-Check compression.
-Check spark
-Check fuel pressure
-Check timing marks
-Check for codes....better yet...check to see if any sensor is out of range using the Honda HDS at a Dealer.

Most of this is going to be shooting in the dark without that base line.

A couple things you can try since there is an obvious issue with idle and higher...

Pull your IAC off and clean the screen. It may be carboned up. That really only accounts for the idle, but it is a start. p246 in the manual.

Pull the silencer on the front of the engine and clean the throttle body as also described on p246 of the manual. If yours is not p246, it should be pretty close.

A couple of potential sensors that it could be is the MAP or the Throttle Postion Sensor. Without an HDS, I am really just guessing, so do not go out and replace them.

You may want to pull the MAP (it is mounted on the throttle body) and inspect it for dirt, corrosion or damage. That would be easy enough to do. I think, if you disconnect it, the ecu goes into a default mode. See if the engine idles ok when you disconnect it. I am not 100% on this...

At least that is a couple of things to try.

Something to keep in mind...the cost of one hour analysis time from a dealer could save many hours of your time and needless parts. And since they can see the engine, there may be something obvious, just by looking at it.
Try to find a dealer who services a lot of 150's. I have found, they do not normally have a lot of problems.

Mike