Honda 150 Maintenance

J

journey on

New member
Just got back from the Catalina Isthmus. They have a Honda dealer there, and I talked to them about the decline in gas mileage on the 150. It went from ~4 nm/gal to ~3 nm/gal. We do a lot of slow cruising. I learned several things:

1. For fuel injected motors, there are two fuel filters in the engine. One low pressure, which you can see when you take the cover off, and a high pressure which you can't. They sold me a new high pressure filter ($40.) I’d only changed the low pressure one, when I got a bad load of fuel, though that was a couple of years ago.

2. Honda has a service bulletin regarding the 2 ea thermostats. If they open too soon, the engine runs cold and takes more fuel.

They also recommended changing the water pump impeller every two years, or 500 hrs.. Over 3 years the motor has 380 hrs.

When I got back to the boat, I said “ I bet I can change that filter right here, on the mooring.” Judy said “over my dead body.” Went back to the outboard shop the next day to pay them and one mechanic had cracked the housing on the filter cage as he changed the filter on another Honda. They ordered a part from the mainland, and the motor was down till then. Luck beats skill. We're now home and I can change the filter with no complaints from anyone.

Boris
 
journey on":2b6e8wch said:
Just got back from the Catalina Isthmus. They have a Honda dealer there, and I talked to them about the decline in gas mileage on the 150. It went from ~4 nm/gal to ~3 nm/gal. We do a lot of slow cruising. I learned several things:

1. For fuel injected motors, there are two fuel filters in the engine. One low pressure, which you can see when you take the cover off, and a high pressure which you can't. They sold me a new high pressure filter ($40.) I’d only changed the low pressure one, when I got a bad load of fuel, though that was a couple of years ago.

2. Honda has a service bulletin regarding the 2 ea thermostats. If they open too soon, the engine runs cold and takes more fuel.

They also recommended changing the water pump impeller every two years, or 500 hrs.. Over 3 years the motor has 380 hrs.

When I got back to the boat, I said “ I bet I can change that filter right here, on the mooring.” Judy said “over my dead body.” Went back to the outboard shop the next day to pay them and one mechanic had cracked the housing on the filter cage as he changed the filter on another Honda. They ordered a part from the mainland, and the motor was down till then. Luck beats skill. We're now home and I can change the filter with no complaints from anyone.

Boris
Click to expand...

Hi Boris,

In order to get anything close to 4 NMPG you'd have to be running in the sub 2500 rpm range using perhpas a couple of gallons per hour (at around 8 knots).

Dropping from 4 NMPG to 3 NMPG is a loss of 25% in your fuel economy. There is nothing that could happen within the engine to account for so much difference short of a major failure of a sensor creating an extremely over-rich mixture.

It isn't possilbe for the filters to affect the mileage since it's the injectors that deliver a precise amount of fuel called for by the ECU (electronic control unit). In fact usually too much fuel is delivered to the fuel rail and there's a return line to send the unburned fuel back the the fuel/vapor separator box. If anything, if the filters were plugged at all they would fail to deliver enough fuel to the EFI system at high speed.

There is no service bulletin on the BF135/150 for thermostats; in fact only 4 bulletins in total exist for the 135/150 and one of them is for a trim item also shared with other models. I have no idea what the folks at the dealership were looking at. There are only two thermostats available for the BF135/150 and one of each is used in the engine; there are no alternatives. Nor would a thermostat account for a 25% change in fuel consumption.

The replacement of the water pump impeller isn't specified in the Maintenance Schedule on the engine as it's a wear item and it depends greatly on how and where the engine is operated. I do agree checking it every 2 or 3 years is a good idea and is easy.

I'm providing this information so other folks have it and so that if you're still experiencing higher than normal fuel burn you'll look for another reason. You should have a Honda dealer hook up the electronic HDS system to check for codes to make sure the EFI system is operating as it should.

All the best...
 
Les, , thanks for your comments, they're for what I'm looking.

I agree with you, clogged filters shouldn't make EFI run rich. but I should of changed that filter when I changed the others. The post on that subject was FYI. And you're right, when we get 4 mpg, we're at 7 knts. As ex-sailors, we're comfortable with that speed, in certain cases. let's you see what's going by.

By the way, I also changed the plugs, as Honda says to do that at 200 hrs. The ones I took out looked great. The same plugs on my Toyota car go 100,000 miles. Both are Iridium plugs, $15 ea. at your local dealer. Or $12 over the internet. No change in mileage.

I don't know what to call the piece of paper that I saw, but it came from Honda, and said what I said, about the thermostats. And yes, there are 2 ea of them.

I figure that there were three things that could lose mileage:
1. Heavy weight. And we may have found a way to pack the boat better and thus heavier.
2. Rough bottom, and that hasn't changed, it's still got the same paint and it's clean.
3. Prop, but the SS prop is the same and isn't dinged.
4. Fighting the current. We seemed to be going against the tide in SF Bay, but got the same mileage going to Catalina.
5. Something in the engine. I'm trying to find a good dealer in Southern California who'll work with me. Sorry you're up north, since the guy in San Diego isn't open on the weekends any more.

Any other comments would be appreciated. I think 2-strokes were simpler, they're just not PC now.

Boris
 
journey on":1eycjpqg said:
Les, , thanks for your comments, they're for what I'm looking.

I agree with you, clogged filters shouldn't make EFI run rich. but I should of changed that filter when I changed the others. The post on that subject was FYI. And you're right, when we get 4 mpg, we're at 7 knts. As ex-sailors, we're comfortable with that speed, in certain cases. let's you see what's going by.

By the way, I also changed the plugs, as Honda says to do that at 200 hrs. The ones I took out looked great. The same plugs on my Toyota car go 100,000 miles. Both are Iridium plugs, $15 ea. at your local dealer. Or $12 over the internet. No change in mileage.

I don't know what to call the piece of paper that I saw, but it came from Honda, and said what I said, about the thermostats. And yes, there are 2 ea of them.

I figure that there were three things that could lose mileage:
1. Heavy weight. And we may have found a way to pack the boat better and thus heavier.
2. Rough bottom, and that hasn't changed, it's still got the same paint and it's clean.
3. Prop, but the SS prop is the same and isn't dinged.
4. Fighting the current. We seemed to be going against the tide in SF Bay, but got the same mileage going to Catalina.
5. Something in the engine. I'm trying to find a good dealer in Southern California who'll work with me. Sorry you're up north, since the guy in San Diego isn't open on the weekends any more.

Any other comments would be appreciated. I think 2-strokes were simpler, they're just not PC now.

Boris
Click to expand...

Hi Boris,

If you ever get the chance to figure out what that piece of paper was I'd like to know...curiousity is killing me! :) I've searched the complete online archives on our Honda dealer site and there is simply nothing (Tech Tips or Service Bulletins) on the thermostats for the BF135/150. The parts microfiche (CD actullay) has only the two thermostats available for the BF135/150 with no number changes since introduction, so suppersessions, and no alternatives. It's a mystery!

The spark plugs are "check" every 200 hours and "replace" every 400 hours. I still think that's way too conservative (and so does the Honda car division) since that's equivalent to about 8,000 miles and 16,000 miles respectively on a car. Of course, as a dealer I have to recommend following the published maintenance schedule. :smilep

Every Honda Marine engine dealer is required to have a Honda HDS handheld computer to "talk" to the engines and a certified tech to use it.

Let us know how it all works out and I'll post more if I can think of anything else.

All the best...
 
I suppose boat engines work much harder than cars. If at 30 mph the boat gets 3 mpg even a heavy car would be getting 30 mpg on a flat road so the boat engine is working much harder and the throttle is much wider open. This will mean the bmep is much higher and so the plugs are more stressed-maybe. Still a change at 400 hours seems to be overdoing it.
 
Your boat engine is basically working the same as a car engine going up a 7% + grade all of the time. When you are going onto a plane more like a 10% grade.

A better measure of wear on an engine in a boat is gallons of fuel used.
 
Was searching for info about the thermostats on our 2007 Honda 150 and came across this thread. My question is, the two thermostats have different temps stamped on them. One is 60 degree C and the other is 50 degree C. On Boats.net, they list two thermostats with two different part numbers. If any body knows if Honda puts two different temp thermostats in the same motor and why it would help. By the way they list for $27 ea. One of the thermostats was stuck in the open position. I will check the other motor tomorrow and see if the thermostats differ in temps also.
 
Dave-

I could understand the 10 degree difference if the lower temperature thermostat is in the base of the block and the higher one in the cylinder cooling area.

Joe. :teeth :thup
 
Dave, yes, the Honda has two different t-stats. The 60'C stat controls the cooling of the engine block. The 50'C stat controls cooling for the cyl head. Don't mix 'em up and if one is stuck open, replace it. Your local dealer should show a list price of about $34 each, right here, right now, no shipping :thup Aloha, Steve.
 
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