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Bf 225 wont idle?

E

escape fisherman

Member
I have a 2003 bf 225 that will not idle below 1100 rpm's . this started a month ago and seems to be getting worse . Now the motor will not get past 3800 rpm's and will not get the boat up on plane. Changed all fuel filters and still doesnt help. Motor seems to be shaking also like it has a miss .
 
Since you do not have an HDS, you need to start with basics.

You said you changed all of the filters. Does that include the High Pressure filter in the vapor separator?

Drain the vapor separator into a glass jar and see what the fuel looks like. Water?

If you have the tool, check the high pressure fuel pressure. You have to remove a bolt at the starboard side of the vapor separator to connect the gauge.

Pull the spark plugs and take a compression test.

If compression is good....next step would be to change the spark plugs if you have not done so already. Be sure to use NGK 1ZFR6F11. Do not substitute.

Those are some of the basics to check.

Mike
 
Ditto on Mike's advice. Also, if you have an external fuel/water seperator, replace the filter. They get clogged up sometimes. Check the pump up bulb when the engine is bogging down to see if the bulb is partially collapsed. If so, you may have a clogged breather tube to your fuel tank. To check, open the fuel filler cap to see if that improves running. The collapsed pump up bulb could also be caused by a clogged pick-up tube in the fuel tank. Blow air back through the tube to unclog.
 
Thanks guys , What tool would I need toncheck the fuel pressure and wohat should the pressure be?I'm going to change the plugs this weekend what should the compression be? Ido have a compression guage.
 
199 - 228 psi. Put shifter in throttle only mode and advance throttle all the way. Disconnect safety landyard to prevent spark.

Compare your spark plugs as you take them out. The one or two that are a lot different could point you to the problem area/s.

High pressure fuel pressure should be approximately 41 - 48 psi.

You will need a fuel pressure gauge with an attachment that can screw into the bolt hole that I mentioned in past post. It is metric and I think it is M6 size (I am not sure of that)..

I am not sure where you are located, but if you have a Harbor Freight nearby, I think this set might work. Take your bolt with you to check the threads at the end of the one hose.

http://www.harborfreight.com/fuel-injection-pump-tester-92699.html

Mike
 
Ok I pulled all the plugs seems like the center tip of the electrode is melted down compared to the new ones , but I have never changed them due to cost. Not to familiar with the new iruidium plugs, is this normal?
 
Not trying to be an alarmist but you had better be careful here! Your increasing idle rpm and loss of power could indicate an intake leak or a cam timing issue. Either of those could lean out the engine and cause those plugs, along with the combustion chamber, to run extremely hot. Don't load that baby up hard until you figure out the cause.

Can you upload a picture of your plug tips?

The iridium plug is very durable.Those are very hard and brittle so it's best that you don't try to gap them. They should come pre-gapped and all you should have to do is check them at the parts counter and exchange for a properly gapped one. They can be gapped but you need to use the proper tool and technique to do it right. Don't use the "ramp" type gap tool.
 
Tips should NOT show any sign of melting. That indicates that the plugs likely experienced a carbon build up, retained too much heat and melted. Install new NKG plugs only, and change out your thermostats because when stuck open they will cause carbon built up. Also change your oil and filter. Oil is likely contaminated at this point.
 
Thanks guys for all the input. I am not running the motor till Ifigure this out . The thermostats were just changed out last fall along with the water pump. There does sound like a valve tap in the motor which does not give me a good feeling. the shop told me that the top end noise I am hearing is the belt tensioner that will need replaced been that way since I got it back last fall. thinking the cams may be out of time? they replaced the temp. sensor and I'm assuming they had to remove belt to do so because of location.Not sure if they got the cam gears right or not. Any thoughts?
 
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