Honda Bf8a Wont Start

[ALAN SWAYSLAND]

Hi guys, I am Alan from England and own a very very humble Honda 8hp 1989outboard that has been brilliant for many years but today suddenly stopped on a river trip. Wife and 2 dogs onboard--just ideal.

I know a bit about old fashioned car mechanics but I cant figure this problem.

I have been unable to restart the engine, normally its perfect.

I have spark at both plugs but the plugs are dry when you take them out the head which suggests lack of fuel.

There plenty of petrol in the tank, the filter is full, the fuel pump appears to be pumping as petrol squirts out of it if you remove the fuel line connection and turn the engine over.

It was suggested by a mechanic that the return valve in the primer bulb could be jammed but as im getting a squirt of petrol at the fuel pump and the filter is full of petrol that doesnt sound right.

Sounds to me like a major blockage in the carburettor although I have never touched it before, do not know how to take it off the engine or what im looking for.

The manual says loosen the carburettor drain screw to see if there is fuel in the carburettor float bowl, cant see where that is at the moment.

Is it easy to remove the carb off this engine--I did loads of this stuff back in the 60s with Ford Motor Cars but of course the engine wasnt dangling over the river !!!!!!

Any help, advice, suggestions etc would be most gratefully received,

Many thanks in advance,

ALAN

 

[gss036]

Re: Honda Bf8a Wont Start

Not something you want to do over the water. The drain screw is on the bottom of the carb, just unscrew it and let the fuel run out, then pump the primer bulb and see if fuel flow back into the bowl. There are only 2 10mm nuts that hold the carb on the engine, look at the linkage, take a picture and you can have something to reference when putting it back together. Honda's have very small holes/openings ,either blow air or spray carb cleaner through them. Hard to find something small enough to use to push through them.

 

[ALAN SWAYSLAND]

Re: Honda Bf8a Wont Start

Not something you want to do over the water. The drain screw is on the bottom of the carb, just unscrew it and let the fuel run out, then pump the primer bulb and see if fuel flow back into the bowl. There are only 2 10mm nuts that hold the carb on the engine, look at the linkage, take a picture and you can have something to reference when putting it back together. Honda's have very small holes/openings ,either blow air or spray carb cleaner through them. Hard to find something small enough to use to push through them.

Thanks for that.

When you say see if fuel flows back into the bowl does this mean the bowl is plastic or glass and you can see the fuel?

Looking quickly on the river at the time I didnt notice it.

thanks

ALAN

 

[gss036]

Re: Honda Bf8a Wont Start

No, you leave the drain screw port open, when you pump the primer bulb, fuel will flow into the carb and out of the hole. At least this way you know fuel if moving up to that point and may just clean out the bowl.

 

[ALAN SWAYSLAND]

Re: Honda Bf8a Wont Start

No, you leave the drain screw port open, when you pump the primer bulb, fuel will flow into the carb and out of the hole. At least this way you know fuel if moving up to that point and may just clean out the bowl.

Thanks now done this and there is fuel flowing through ok, however despite having checked out the petrol pump, spark at plugs and replaced all the petrol with fresh petrol as water in petrol was suspected ---still dead as a dodo.

Plugs seem to be wet---its been suggested there may still be water in the system although stripping the carb may be the next move.

Before stripping down an idea from someone is to spray damp start into the air filter--good idea--bad idea?

thanks

ALAN

 

[gss036]

Re: Honda Bf8a Wont Start

There really is not an air filter but since it is a 4 stroke engine, try spraying fuel or starting fluid to see if you can get a a kick out of it.
Once you have drained the carb bowl, there is no place else for water to hide.
Have you put in NEW spark plugs? The next thing would be to check for compression, just by chance it is a valve problem.

 

[ALAN SWAYSLAND]

Re: Honda Bf8a Wont Start

There really is not an air filter but since it is a 4 stroke engine, try spraying fuel or starting fluid to see if you can get a a kick out of it.
Once you have drained the carb bowl, there is no place else for water to hide.
Have you put in NEW spark plugs? The next thing would be to check for compression, just by chance it is a valve problem.

Thanks again for the ideas im working through them.

I havent tried changing the plugs but would the engine suddenly die on me--no misfiring just big loss of power--from my experience of old cars it seemed unlikely but I will try everything.

It did occur to me that either there could be a valve problem or even some loss of compression due to a blown gasket--does this engine have a head gasket like a car?

Im off to the marina boat shop to buy some damp start and for some more ideas---any other suggestions welcomed otherwise I may have to lift the engine and take it home to my garage to work on it---still I do have the whole winter here in England to fix it!!!!!

thanks again

ALAN SWAYSLAND

 

[ALAN SWAYSLAND]

Re: Honda Bf8a Wont Start

Thanks again for the ideas im working through them.

I havent tried changing the plugs but would the engine suddenly die on me--no misfiring just big loss of power--from my experience of old cars it seemed unlikely but I will try everything.

It did occur to me that either there could be a valve problem or even some loss of compression due to a blown gasket--does this engine have a head gasket like a car?

Im off to the marina boat shop to buy some damp start and for some more ideas---any other suggestions welcomed otherwise I may have to lift the engine and take it home to my garage to work on it---still I do have the whole winter here in England to fix it!!!!!

thanks again

ALAN SWAYSLAND

UPDATE

Looks like it might still be fuel contanimation.

A sample of petrol taken today according to a mechanic still contains bubbles of water and some red sediment--possibly rust out the petrol tank.

I have taken the carb off to give it an overhaul and clean---plus I will most likely have to replace the petrol tank.

Will update asap

ALAN SWAYSLAND

 

[ALAN SWAYSLAND]

Re: Honda Bf8a Wont Start

UPDATE

Looks like it might still be fuel contanimation.

A sample of petrol taken today according to a mechanic still contains bubbles of water and some red sediment--possibly rust out the petrol tank.

I have taken the carb off to give it an overhaul and clean---plus I will most likely have to replace the petrol tank.

Will update asap

ALAN SWAYSLAND

UPDATE

Report from local repairer is low compression.

However no proper test was carried out so I am buying a Compression tester myself to double check before ripping the engine out the boat for a strip down.

ALAN SWAYSLAND

 

[Murp]

Re: Honda Bf8a Wont Start

1- Compression test,,2,,New Fuel,,3,,Spray Carb Cleaner in Fuel line going to Carb,,4,,Check Needle Valve and seat for wear marks,5,,Disassemble Carb soak in Cleaner and Blow all Passages out with Carb and Choke Cleaner

 

[intrepidvoyager]

Re: Honda Bf8a Wont Start

Hi Alan ....for every engine that won't start due to low compression there are 100 that won't run due to fuel issues .... get a new tank and fuel line .... also clean out the fuel pump cranking the engine with fresh fuel .... pull the fuel line of the carb ... new filter of course ..... when you do this put paper towel over a container and make sure no crud comes out of the fuel pump and that its pushing fuel .....you have to make sure the carb is really clean .... now if the engine starts and runs ...great ....if it starts and dies you still have a fuel issue so reclean the carb ...... Do you have a choke or bystarter ?

Toad Hall Grad

Cheers