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BF150 max 3100 RPM's need help

M

mcgyver

Contributing Member
water test today with 2005 BF150 new to me and my 21' center console. previous engine was a 150 yamaha 2 stroke 19 pitch prop. Engine started immediately (purred) and motored out of the marina fine. went to get on plane and couldn't get it to rev over 3100 and didn't get on plane, 3 tries with trimming ect and then motored back to the launch. When I disengaged the shifter at the binnacle, i can easily rev to 4500+. I'm at a loss which direction to proceed.... filters ect, or reprop from the 19 to more like a 15..is 19 too much pitch for the weight of the boat and hp of the engine? or is it a fault in the engine not developing enough power and is that the route I should go first. Suggestions?
 
Make sure that the throttle lever on the motor goes all the way to the stop on the engine.

Check the height of the motor. The cavitation plate should be approximately parallel with the bottom of the boat. if you have a jack plate, then the motor should probably be mounted about an inch higher.

Check the following site for various boats that have been tested with a 150 Honda. http://marine.honda.com/products/performance

It should help you zero in on the correct prop. The 19 may be a little large but not 2900 rpm worth.

It could be an engine problem, but I would check the rigging first.

Mike
 
Mike, rigging seems fine. I had it out again, managed to get it on plane max 4800 RMP at 30mph (took a long time)(very slow for 4800rmp), no power at top end and if I dropped off the throttle just a bit it would come off plane...couldn't get it on plane again. therefore losing hp/power at the top end. Now I'm convinced that it is an engine issue..... I'm thinking of replacing plugs, fuel filters (high and low), draining VST (is that nneded ie would it cause these problems?), what else would you do before another water test? Under no load it purrs up to about 3500rmp where i stopped. I'm stumped and the closest dealer to me is 50 miles.....
thanks
 
here's where i'm at with this: drained the VST (clear no water or gunk), checked low pressure fuel filter (looks like new), no water and clear in the fuel/water separator, High pressure fuel filter looks like new, no kinks in the fuel line anywhere, plugs are the right kind 1zfr6K11 but i will change them just to be sure. Now: when i short the SCS circuit and turn the engine to on I get a solid MIL light that does not go off. there are 4 causes to this 1. open circuit in the ECM power supply 2. short in the data link connector wire 3. short in the MIL wire 4. faulty ECM. My manual says to connect the test harness and then go through a logical test of voltages and resiatance to test each one of the 4 causes. My question is, do you think that 1 of the 4 could be causing the symptoms I'm experiencing? Will a diagnostic test by honda now be warranted? and will that pinpoint the problem?
Thanks
 
The solid mil light also can mean that there are no codes.

Assuming that is the case, there are a few other things to check...
Is there any blockage to the intake?
Is the IAB control solinoid functioning?
Is the VTEC functioning?
How is the compression of the cylinders?
How are the valve clearances?
Leak down test is you suspect something internally wrong.

I assume you have a manual, from the way that you are quoting MIL conditions.

There are detailed tests in the manual to check those things I listed.

Still could be to much pitch on the prop. A 17 pitch might be better. If you can borrow one from someone to try. Even if it is a Mercury prop for a test.

Make sure the motor is not mounted too low.

Mike
 
compression test, 175 psi 1,2and 4 #3 140 psi. I'll now do a wet test to try to determine valves or rings. If valves 9and i have my fingers crossed) then decarbonize treatment with seafoam and possible valve adjustment check. Mike, do you think that 40# drop could cause my symptoms?
Thanks

BTW Dark, if the prop was spun, I should have been able to easily get the rmp's up but woldn't have been able to get on plane....been there done that once...made me look like a fool till I realized that i had spun the prop on the 9.9!!!! reving away and hardley going anywhere! thought the tide wasn't running that hard!!! ;-)
 
The sick cylinder could very well be a great part of the problem. A none scientific thought is if only 3/4 of the cylinders are doing their thing, then 75% of 6000 rpm is 4500 rpm, which is about where you are.

Hopefully, your decarbinizing and valve adjustments help. Compression is supposed to be 222 - 250lbs at 200. rpm

You still need to make sure the IAB control and vtec solinoid are operating.

Mike
 
Nope......just got done with the decarboning, compression check again, #1 200psi, #2 205psi #3 160psi #4 200psi, wet tested #3 and went to 195psi. At this popint mike what's going to be involved? i know they will do a leakdown test, but what will it be from there do you think? and what kinda costs will i be looking at? What would you do next?
Thanks for your help
 
It is interesting that all of the compression values went up 20 - 25 lbs. A lot depends on what the leakdown tells you. Still could be just valve clearances, but that is pretty optimistic. Sounds like there may be a ring issue.

The HDS will let them check all the other parameters. Although, the compression issue is pretty important.

It should not cost too much for a diagnostic check. They should have a basic charge for that, which they should tell you up front. Then they should be able to give you an estimate to fix it.

Mike
 
Did an overnight soak with straight seafoam (about 1 oz) in the 3rd plug hole with the engine raised. Put in about an oz of oil (to lube the cylinder) before plugging her up and testing. Warmed her up for about 5 min then did a compression test. #1 200 #2 200 #3 170 #4 210..... encouraging for a stuck ring ect. I've got her schedualed for a hds test and leakdown plus whatever else the tech wants to do thurs. will post the findings. Thing is it starts and idles beautifully, runs beautiful with no load up to about 3500, no smoke whatsoever, on the outside you wouldn't think anythig but perfection! Will find out Thurs...have my fingers crosssed that my season is not done....any major repairs would be outside the wifey's, i mean mine, fishing budget for the year!
 
Final verdict.................. thrust bearing failure, dropped crankshaft and flywheel..... engine is completely pooched....:-( i'm going to go and cry some more.......
 
Sorry to hear that. I assume no "implied warranty" from the person from whom you purchased it.

Better luck to you in your future purchases.

Mike
 
Mike, I have a 2006 BF150. I do regular maintenance and all is well. What would cause such a massive failure? Anything to lessen the likelihood?

Bill
 
Sometimes it just happens....most likely not frequent enough oil changes. If you run the engines hard as in commercial use, you should change oil before the standard 100 hour mark.

There may be other thoughts out there...I have only heard about these kinds of failures....never seen one first hand. We normally, stay on top of our customers who use their 150's, 225's etc commercially or have heavy use .... and badger them to service regularly. Fortunately, the local Fire/Rescues and Police Department have incorporated that into their standard practice for periodic maintenance.

Mike

Mike
 
Honda mechanic told me that this is not an "uncommon" failure (first thing he looked for! flywheel had dropped and was rubbing on a sensor!) (only cost me 1/2 hour diagnostic! and didn't even do the HDS!) but honda refuses to recognize it and put out a bulletin. he's not sure if it has been addressed in future years. Mike, what would be involved in tackling this myself over the winter? Engine is basically worthless other than the leg, and i'm mechanically inclined...special tools ect?
BTW thanks for all your expertice and help....
Doug
 
Sounds like you have a pretty sharp Dealer.

Assuming the head is probably ok.
Ask your dealer what they think.

You could purchase a short block and gasket set for about $3500 retail. Of course, your time is priceless...and the rest of the motor would still be older.

I can not comment on trying to disassemble the block and do a rebuild. If you have the capabilities, then it might be worth it. I go for the short block...based on my limited experience and the customer's desire to get back on the water quickly.

It still takes a lot of uninterrupted time to tear it down and put it back together. That is a luxury that I normally do not have, due to other customer situations.

Let us know what your dealer thinks.

Mike
 
Ended up with an expensive anchor, too much risk trying to rebuild when i don't know the extent of where/what those thrust bearings/pieces ended up affecting in the crankcase. Like Mike said, new smallblock on an older leg ect doesn't make much sense. Boat sits for the season, will look into options for repowering over the winter..... BTW talked with Honda and although they were sympathetic wern't willing to take any of the resposibilty for the failing thrust bearing, i personally now know of 3 BF150's 2004-2006 that this exact fault has affected.:-( Doesn't give me a warm and fuzzy over honda outboards.....
 
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