Engine will not start - advice please

oGaryo

oGaryo

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Hi again, for those that can recall waaay back, I was looking to get my first boat in the winter just gone by but due to financial 'negotiations' I've had to downgrade my aspirations for this year and instead of getting a sportcruiser I've purchased a 1998 Bayliner 1750 with 3.0l inboard.. + a no expense spared trip to disneyworld for the family + a pair of tickets to wimbledon quarter finals for me and my lady :-( The latter two being the reason for lack of coffers this year.

The guy who sold it to me let me know it had been laid up for two years on his drive and would need an engine and drive service.. however, he showed my the engine running, albeit roughly.

Got it home and it's gone from trying to start (engine splutter's) to cranking over but not starting at all, doesn't even try to fire up now.. I've done some diagnostic work checking the battery, plugs, distributor cap and the like and have fixed a few obvious things like removing the crud off the points in the cap, cleaning earthing points and giving the plugs a clean..

I think I have a fuel supply problem from the carb to the engine.. can someone confirm please before I go buying a kit to service it (or putting it in for a service more like along with the engine and leg).

The reason why I think this is that I get a good spark at the plugs, cylinder compression is in the green on my compression gauge, I get a squirt of fuel (two jets) in the carb intake when I pump the throttle so supply to the carb looks ok but when I turn the engine over several times and look at the plugs immediately after, they're not wet with fuel hence suspecting I have varnish or particle blockage within the float chamber and ducts feeding the engine. As there's no sign of fuel getting to the chamber's, I'm not suspecting poor fuel condition yet but it's likely it'll need changing I guess even if the engine was running a few days prior to my buying the boat.. finally, I can smell fuel after cranking the engine which I suspect is the carb float chamber flooding as the fuel has nowhere to go due to some blockage on the engine feed side of the system.

What's your advice please.. strip the carb down or are there further checks I should make first before dismantling it? e.g. even though the switch on the throttle is set to 'run'... could that have a dodgy connection?

by the way.. it's a mechanical fuel pump by the look of it (no wires going to the pump).

loving this boating thing already LOL taking a cup half full outlook, at least this boat's enabling me to learn loads about the mecruiser engine before parting with some serious cash next year on a bigger boat and it was running a few days ago so the rest of the engine is likely to be ok.

cheers Gary
 
Could be sticking float in the carb if the spark is OK, which it sounds like. After a long layup the carb bowl could be full of sludge so worth stripping the carb and cleaning the jets and other internal fuel routes.
 
Go on, strip the carb. You know you want to. That's the beauty of older, non-EFI engines - you can take it to bits. As I had a problem twice at sea with sticking butterflies on our old 25hp outboard, I'd say it's worthwhile taking it to bits now on the drive so you are familiar with it.
 
Has the fuel also been standing for 2-3 yrs? You'd expect it to at least splutter if that was the only cause, but it's an easy one to discount by trying some new fuel.
 
thanks guys..

Kill Switch is set to run but I've not tested it for 12v.. the fuse board is salted slightly so will be checking out a few minor electrical issues too such as the horn not working.

The fuel has been standing I think but I'm unsure if any stabaliser was used.. he did say he'd winterised it again this year but I didn't think to ask if he'd done the fuel too.

I've had a bit of advice in a pm that I'm going to follow through on tonight that involves fuel mesh filters in the base of the pump and intake to the carb + there's a jet accessible without stripping the carb down that I'll check too.

Gut feel is I'll end up doing a full carb service even if I get the engine to start.. just for peace of mind on the water.

A few other things I've not mentioned yet is I've put about 15ltrs of unleaded fuel in (BP Ultimate 98ron) as the tank was virtually empty.. I did this 'after' the engine failing to start thinking it may be a fuel feed issue due to emptyish tank. Really hasn't occurred to me either if it's ok to use this fuel.. I've assumed it's the same as that sold in the marina's?

I've also taken the carb off the engine mount once already just to have a look at the general condition of the underside and to be honest there's very little in the way of varnish there and the ducts look clear, however, that's not where the fuel will have been sitting for the last 24 months(float chamber will be the problem I guess)

Keep the advice coming please, this is great stuff and helping my thought process greatly...

p.s. please be candid if I've done a bad thing by putting good fuel on top of bad.. don't mind being called a wally if the evidence is there LOL ;-) I suspect that was a mistake and really, I should have had the old fuel system drained before attempting to start the engine.. I am where I am and again, appreciate your good advice
 
Hi
The only point I picked up on was that you state there is fuel squirting from 2 jets, so fuel is getting through. So do you get any form of attempting to start, are you pumping the throttle when trying to start the engine?. Surely if fuel is squirting in there must be something happening if the plugs are not getting wet.
If it was the 'kill' switch then you would not be getting a spark.
 
Hi Peanuts, that's my conclusion also.. air, fuel and a spark and something should go bang.. I have the spark so it's either air or fuel and with it degrading each time it was used I'm suspecting a progressive blockage i.e. the more dirty fuel that was pumped through, the more the blackage took hold.. time for a clean up.

p.s. to check it wasn;t the strength of the spark, I removed the now drained marine battery and put my car battery on there, still nothing in terms of the engine firing... marine batteries now on charge out of the boat.
 
Your carb jets are blocked, pumping the throttle only shows that the accelerator pump works and that fuel has reached the float chamber. You are not proving main and idling jets. You can check the pump by disconnecting the carb feed pipe and cranking the engine, if fuel spurts it's fine.

Strip the beast down, get it cleaned, airline all jets and jetways, check for aluminium salts blocking jet ways, if you see any white encrustations on strip down you need to poke out jetways with the jets out and blow it all out. Check the diapraghm for pin holes, change it if necessary (assuming it's that type of carb) or clean the damper on SU type carbs with brake fluid to remove tar residues and refill with light oil. That should sort the carb out.

NB - when unscrewing adjustable idle jets, count revs to remove and refit the same amount of turns, final tuning to be done when the beast is running.
 
going to give everything a good going over tonight... will use fine wire from a multi core cable to poke the holes out and I have one of those pressured air in a can things that the computer bods use.. will see if I can get away with putting it back together without new seals for now until I order a full service kit.. bad idea? should I wait until I have the service kit? cheers
 
Have you tried squirting some Easy Start into the air intake. This get the engine starting, and it may pick up from there. Otherwise you have had a lot of good advice. But, tendency is to look at the difficult things first, when generally it is the simple things that cause the irritating problems. Using the high grade fuel will only have a positive effect, no real downside, except cost.
 
Hi have you tried giving the carb a good soaking with carb cleaner? Can you easily take the top of the carb and see if there is fuel in the float chamber? If you can get the top off hold it the right way up and see if you can blow into the fuel inlet, if you cant the needle valve isn't passing fuel, if you can then check that when you move the float up that you can't blow into it. Is the choke mechanism working ok, not familiar with the carb on your engine but some are electrical. Potentially dangerous but pouring some raw fuel into the carb can make them go, safest to pour in then crank but don't overdo it. Is there an anti diesel valve in there anywhere? opens the manifold to atmosphere or shuts off the fuel when the engine is stopped to stop it running on. One thing I have found helps is to heat the working end of the plugs with a blowtorch or on a gas ring, you need to be quite quick so they are still warm when they are put back in and you crank the engine. Have you put a new set of plugs in? I would do this as a matter of course if an engine is reluctant to start.
Is there any possibility that the ignition timing has moved?
 
the good advice keeps one coming :-) thanks guys.

Have just purchased a new set of plugs NGKR BPR6EFS (that's what's fitted now).. as the original set looked old and rusted in places and there's a hairline crack in one of them.

A bit reluctant to start squirting easy start and the like in the intake to be honest until I know more about marine engines.. feel safer keeping the fire arrestor fitted.

One question, once I have the carb dismantled if indeed I go that far (think simple first as above).. do you think a mixture of strong redex and petrol to soak the parts in overnight would remove any residue/varnish? I have some in the garage so it's convenient if it will.
 
So long as gaskerts/seals are intact I wouldn't bother for now, you can always put some Hylomar on the inlet gasket to avoid weak runnning due to air leaks. I doubt an aerosol will have the power to blow that hard, can't you nip down the local garage and borrow theirs on the spot?
 
We had a very old Mercruiser 170hp straight 4 lump of around 3 litres some years ago, and it was a bugger to start. A squirt of Easy Start did the trick everytime, so I wouldn't worry about that. I've started a reluctant motorbike using a gas lighter refill before now. Just don't try to use Easy Start to kick start an Eberspächer...
 
I think I'd go with the easystart suggestion. Not necessarily to start it but at least to see if it fires or not. It will point you in the right direction as to whether it's electrical/timing or a fuel problem.
 
If you rapidly “pump” the throttle whilst cranking the engine the accelerator pump will chuck enough fuel in to fire even if not to continue running regardless of any blocked jets. At least that will confirm it’s a fuel problem.
 
here's a simple question for you :-)

just fitted the new spark plugs and noticed the HT lead configuration is in a firing order of 1:4:3:2as per the diagram in the GAS engine Alpha models (3.0l) booklet that came with the boat.

However, on top of the fire supressor, it states 1:3:4:2!!

Majorly confused as to which one I should go for.

Can anyone give me a rock steady answer for this engine please.. I can get the details of the engine if that helps other than it being a Merc 3.0L 135bhp unit.

thanks again, Gary
 
Easystart is not a bad idea, should get it to fire up. Ok to use on a petrol but best avoided on diesels. If you can get it to fire, as David2452 says you should be able to keep it going using the accelerator pumps. If you can get it to run even roughly briefly block the air from getting in by putting your hand over the carb intake several times. This will encourage the engine itself to suck the crud out of the jets. You will need to take the flame arrestor off, if you are concerned have a fire extinguisher to hand. Best to make sure you let any fuel spillage evaporate between starting attempts.
Another thing to check is if any engine breathers go into the manifold after the carb, if so make sure they aren't drawing air.
Proper carb cleaner is the best thing to use to clean carbs, your local motor factor will have aerosols in stock.
 
Aha, so it is the straight 4 lump that I used to own (sorry, I got confused over the hp). It was always a b1tch to start, in that case, and EasyStart did the trick every time. It 'burped' once, throwing a big jet of flame out of the carb when I had the air cleaner off, but it was never any bother.
 
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