Honda BF75A Telltale intermittent water output

[CW180]

Hi guys - I got my engine hooked up yesterday and decided I'd give it a run today so I can start trying adjustments to get the throttle & gear cables set up nicely etc,

I seem to have a couple of issues though with the engine.

The first is that the water output from the tell tale only happens some of the time. I realise that running the engine without water being pumped through can cause serious damage so I am anxious to resolve whatever is going on here.

The first time it started, it ran for some time with no water coming out, then suddenly it started peeing out of the tell tale like it should have been. I'm not used to Hondas (previously had Yams) and I wondered if Hondas vary the amount of water they pee out for some reason? It was absolutely blasting out for some time - really powerful healthy jet, but then after running for 5 minutes or so the water output reduced.
There was another time as I recall when nothing was coming from the telltale, but both times when it has done this, I switch the engine off, and then water begins to pour out from it, even though it wasn't when the engine was running immediately before.

It's confusing me somewhat I must admit!! Is it possible there's something inside the engine in a waterway that is moving about and sometimes causing a blockage and other times not? I can't think why else the water output would be fine at some times but not others unless it's something like this, ie if the impeller was damaged then the flow would be reduced/stopped all the time, not sometimes.


The second issue is that the engine bogs if I try to rev it much. I suspect it's fuel starvation.
I've only just hooked up a new fuel hose from my onboard tank, and I rather think that the connector on the end of the hose where it attaches to the engine is not sealing correctly. I want to get a genuine honda connector as I think it's a cheap aftermarket one that's leaking air in, but are there other common issues that could cause this behaviour that I can easily test for?

Many thanks in advance

 

[Nuaticocat]

Re: Honda BF75A Telltale intermittent water output

If the pump indicator is intermittent, it is likely that the impellor has dropped a fin. Drop the lower unit and change the impellor in the water pump.
Change the fuel connector to the honda part.

 

[CW180]

Re: Honda BF75A Telltale intermittent water output

Thanks for the reply.

When I say intermittent, I don't mean that it pulses like I would expect it to do perhaps if the impeller was missing a fin or two, but it can sometimes not pump for over a minute, then suddenly start jetting out absolutely fine, then stop again later.

I wondered if perhaps the thermostat being closed would prevent water coming from the tell tale, but outboards I've had in the past have always output water from the telltale regardless of stat position.

I have however found this description in the manual:

"Amount of water flowing out of the check hole might vary due to the thermostat operation, but this is normal"

It's hard to know whether this is referring to a mere change in intensity of the water output jet, or that it may start and stop completely dependant on the stat position?

 

[CW180]

Re: Honda BF75A Telltale intermittent water output

I believe the impeller and so on were checked as serviceable by the dealer I got the engines from (it's one of a pair and this is the better of the two), and I know it has also had an oil & filter change etc. I've owned them a few months and this hasn't run for more than a few minutes in that time as it hasn't been on the boat.

Well I took the liberty of removing the stat housing to inspect it, since I've had ones with salty crud in before when previous people haven't flushed adequately.

Bit of a shock actually the amount of gunk in there:

Impressive! I should add most of this was from the housing where the hose flush pipe connects to, just to the side of the stat housing, but there was still a bit of gunk in around the stat. All of this is nice and clean now anyway!

I also removed the lower valve housing about 8 inches below the stat and cleaned that out. There was a small hole that was blocked in there but otherwise not too bad.

I also tested the stat in a pan of water before reassembling and it seems to work ok.

So I reassembled and started the engine after it has been sat overnight.
It peed out a very good jet straight away, and this carried on for a couple of minutes maybe, then the jet got weaker and stopped. I switched the engine off quite quickly after this even though the overheat warning wasn't on.
I thought I would let it cool for a few hours as I'm out for lunch, then repeat and see if it behaves the same way.

I've a suspicion that the flow is stopping when the stat opens, since it was fairly definite a couple of minutes or so after the cold start and I'm sure that could coincide. No idea why that would be the case though?

 

[Nuaticocat]

Re: Honda BF75A Telltale intermittent water output

Sounds like you might have several problems. I would stick the motor in a trash can full of water and let it run. Monitor the temp of the water. If the water pump is working correctly, the water in the can will get hotter. I am not positive with that engine, but i don't think the telltale is affected by the thermostat. I would think your first concern would be for flow , and then temp.

 

[CW180]

Re: Honda BF75A Telltale intermittent water output

Thanks - the engine is in a 50 gallon drum so it gets plenty of water.

Think it would have to run for a very long time to noticeably change the temp of the drum water with that sort of volume.
I have noticed earlier with my hand in the pee stream that when it was warm it would very quickly sometimes alternate between warm and cold etc, and I'm not sure why that would be, but it's not something that's worrying me as such.

Might try it without the stat to see if it affects how long it pees for happily.

I also need to sort out the fuelling/rev issue as well, and that could be any number of things, so at this stage whereas I was hoping to get out for a test run in a few weeks I can't see it happening for a long time, and then we'll be into winter when it's really not likely at all.

 

[CW180]

Re: Honda BF75A Telltale intermittent water output

Just been out and given it another run. Progress I think!

I'd drilled out the pee hole from about 2mm to nearly 5mm to aid the flow of water and reduce chances of blockages, plus I gave all the linkages etc a liberal spray of WD40 and worked them all back & forth many times to ensure everything is moving freely as it should be.

Started the engine and water blasted out nicely from the telltale. Carried out letting it run at a fairly quick idle (tacho not wired in yet) and the water continued to flow. I did some tweaking of the throttle stop screw on the bottom carb to raise the idle a bit initially as it kept stalling.
Carried on revving it, with regular short squirts of carb cleaner into the air intake.

After it had been running for some time I found that it actually was much happier to rev now. It seems like it sounds a bit rough to me but it's so hard to know what's rough and what isn't on an engine I've never really used before, and when your head is a couple of feet from an open intake that makes a huge amount of induction noise when you rev it!
Initially it was coughing each time I tried to rev, but after it had run for about 10 minutes it began to rev ok. I realised a moronic schoolboy blunder - where I'd thought the neutral throttle was making it run rich and bog, it was of course because I had pushed the lever into the choke zone while the engine was already warmed up (hangs head in shame).

Anyway - I ran it for the better part of 20 minutes in the water filled drum, and no hesitation in the telltale flow this time at all. Constant and strong stream of water. Plus it now appears to rev without coughing or bogging.

I think this may be a case of blowing out the cobwebs from an engine that's not been used for some time. The idle seems very smooth, and with the engine cover on, it's a pleasantly quiet motor (if louder than my 1999 F50 that I had before).

Will continue to give it a run in the tub each night I think and ensure it runs nicely and behaves well, plus I will get some sort of fuel treatment to go in and potentially help clean stuff (although I think they're mostly snake oil, there's no harm and you never know...), plus if I can get an additive for the water to help get the salt deposits gone I'll do that too.

So I'm a lot more positive now than I was earlier in the day, and that's not bad progress I think.

 

[CW180]

Re: Honda BF75A Telltale intermittent water output

The next thing I need to address is that there are no lights on at the remote box, at any time that the ignition is on or engine running.

I understand that normally if the light goes out this means low oil pressure but I seem to recall my dealer telling me when I took the engines off him* that one of the control boxes of the pair had an issue with the warning lights, and that these hondas are notorious for something to do with the alert system being oversensitive, or giving false alarms or something. I forget the details now and I wish I'd written it all down at the time.

Anyway - possibly I hooked up the wrong one of the two I got, but with no lights showing at any point is there an easy way to investigate this? I seem to recall when looking at one point that these things use neon bulbs that use funny voltages and aren't easy to test or something?

*I got a nice deal from him - gave him my 1999 yam F50 low hours for a pair of 1996 BF75 high mile engines - so it was with caveats about the condition of these engines

 

[CW180]

Re: Honda BF75A Telltale intermittent water output

Update time again - gave the engine another 15 minutes running tonight.

Started very easily from cold, even on the very small, very old lucas battery I had from my F50. Running it like this really seems to be helping blow out the cobwebs from the engine. Very briefly popped it into forward & reverse gears, although I can only do that for a few seconds due to the eruption of water that then leaves too little in the tub.
The pee stream from it was really solid until around the 10 minute mark or so when it began to lose pressure/flow, so I turned off the engine and left it while I did some other stuff.

I got battery terminals today, and a load of high current ring terminals, so I took the croc clips off my jump leads (really thick 41mm2, 2 gauge cable), and put the terminals on both ends. I bolted them up to the engine power leads, and the battery, and cranked the engine.

Cranks over very nicely and fired up no problem. I took the caps off the spark plugs and cranked the engine a bit to see how quickly it cranks and the combination of the new 105ah battery and the thick leads really whizzes the engine over at speed. Healthy starting assured, and this is great because it means I can move the 2 batteries to underneath the console. This will definitely help balance the weight of the BF75 and BF5 on the back by moving 30 kg or so forward rather than it being astern.

Made an interesting reminder of just how crappy the clamps on jump leads can be compared to a solid connection. These a decent quality 3.5m Clarke 41mm2 leads, but hooked up to the engine with clips it was sluggish and reluctant to crank over. Swap to proper battery terminals and the right size ring terminals on the other end (with m8 bolts to connect to engine wires) and it goes at real speed! Huge difference and demonstrates the importance of a good electrical connection for anything with a load to feed.

Picked up 3 gallons of vinegar to help flush the salt out, so I need to displace a lot of the water in the barrel so the vinegar is not diluted too much.

Yesterday I bought a can of seafoam online so will be interesting to see if this makes any difference to the general engine behaviour. It's running fairly good from what I can tell, but I doubt it's quite as refined as it should be yet due to age & neglect of previous owners.

I was also a bit naughty and ordered a copy of the honda carb manual, and a genuine paper service manual. Already have digital copies of the service manual but they're limited use when they're scanned docs that you can't search words etc. Costly to get the printed ones but will be worth their weight in gold.

Also, I might just have found me a set of sensibly priced 90 carbs to upgrade from 75 to 90. Now that would be nice!

 

[CW180]

Re: Honda BF75A Telltale intermittent water output

Got a chunk of the console wiring harness made tonight. Tedious as hell to do, but it will make things easier to have it labelled nicely and measured to the correct lengths & soldered/heatshrink covered etc etc.

 

[Nuaticocat]

Re: Honda BF75A Telltale intermittent water output

Man, you have a lot of stuff going on! Seafoam is a good product. Have you cleaned the carbs at all? I use berkible 2+2 carb cleaner. Take the carbs off and spray all the accesible orifices. Works like nothing else for getting varnish out. I would be a bit leary of just going to 90 HP carbs. Get the engine screamin first , gain some time in the water on it , then look at bigger carbs. I suspect the larger carbs will provide too much fuel, but I am not an expert on Hondas.

 

[CW180]

Re: Honda BF75A Telltale intermittent water output

Yep - pretty busy with it all. Big list of jobs still to do admittedly.

Haven't had the carbs off or cleaned them other than spraying carb cleaner into the intake while the engine was running.

Will look up that cleaner you mention but I'd be surprised if it's something I can get easily in the UK. Was bad enough with the seafoam costing ?22 for a can (about $35!!)

If I can get a set of 90 carbs then I definitely will, but I wouldn't be fitting them to begin with. I want to see how the boat performs with a 75 on it before changing it to 90 spec. The carbs are the only difference between the two engine sizes with these motors, so it's an easy upgrade to do. Actually, not entirely true as the stickers are different as well!

Off work today and tomorrow so will see how much time I can sneak in on the boat. Hopefully get the wiring mostly done.

 

[CW180]

Re: Honda BF75A Telltale intermittent water output

You know that horrible moment when it dawns on you that you've spent ages doing a job that really wasn't necessary at all?

Yeah, I feel like an idiot now. I just found that on the really old & manky looking remote box that was on the boat when I got it, that it has the separate wiring harness for the gauges attached to it and I'd never even noticed. How dumb do I feel now after spending about 2 hours last night making a new harness!!!

On the plus side, I tried starting the engine with each of the honda remote boxes that I've got (two came with the pair of engines, and one was on the boat when I got it), and out of 3 of them there is only one which displays the green warning light.
The other light I hope only comes on when the engine gets hot, as that does not light up on any of the three.

It's a shame as it's the scruffiest, mankiest looking one of the 3 that has the working warning light, but possibly I can swap the casings, or else troubleshoot the wiring of a non working one against the good one to figure out why the lights don't work. At least it confirms the oil pressure is fine. I think.