outboard help

H

hollygolly

Well-known member
good day people.
i have an evinrude 75hp 2 stroke outboard, 1983 model. runs well on trailer and in tub, throttles great, goes in and out of gear. as soon as it is in the water and you attempt to put the throttle on it dies. It will run on idle, and will go into gear and run on idle at about 3knots, but try any throttle and it dies. I have had the petrol pump off and stripped, carbs have been off and cleaned twice now. fuel lines checked and pump fuel ok...anyone help with this problem? Or does anyone know a good mechanic in Hartlepool?
Look forward to your replies.
Just to update, i have refurbed the petrol pump, with new petrol lines, fresh fuel (Shell optimax not the supermarket crudge) swapped the carbs for a different set which i cleaned out before fitting. I now have some revs but it still cuts out before reaching top revs. I now put this down to the prop (17pitch) or the fact it was still on the trailer when in the water (wanted to give it some load), so will now drop it in the water next weekend to test better.
 
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We had an old force 75hp 2 stroke once that acted similar.

Turned out that the gear / throttle linkage on the enigine was nipping the fuel line as you pushed the throttle.

Couple of cable ties sorted it.

Probably not this as you say it's alright on the trailer, but thought I'd mention it incase, worth a look.
 
sounds the same problem as i had with mine to much fuel getting through and not enough spark to egnite it try a new sparky or yr fuels got to much oil init if not this could be the points
 
hi, thanks peter.
Changed plugs, good spark, fuel 50:1, fuel pumping through seemingly OK.
Not sure they have points like a car engine do they? I am told that they have a power pack or coil type condenser on each pot? May have to change them. Was told if it was not fuel it would be something electrical...not a lot else after that really is there?
Having said that i note some black sludge coming from the exhaust behind the prop which could be unburnt fuel? cannot be gear oil as it is grey or red int it?
Thanks
Peter
 
mine has got points under the fly wheel could be worth taking it off and checking them have you got a manual for it, if not get someone who no's how to check them using a feeler gauge but you will need to no the clearances first mite be worth trying to find a manual on ebay or elsewere
 
When you say it runs well in the tub, do you mean it revs up ok not under load.
Just wondering if the advance and retard mechanism is working. If it is not reving up, start the engine in the tub, squirt some petrol into the air intake as you open the throttle, if it revs, then the engine is being starved of petrol which would indicate a blocked jet or fuel filter somewhere.
Was the engine running ok last time it was used, if so, any petrol left in the carbs over winter could have solidified into jelly causing a blockage.
If all else fails, could be the trigger switch or the stator under the flywheel.
 
I can probably fix it, or tell you what to do.

New fuel.

Start by removing the prop get it in a barrel of water.

Start the engine.

Let it warm up.

Then gentaly increase the revs.

If it cuts out as you increase, remove the carb, strip and clean in neat petrol.

Next use spark plug testers and do the same. Now it gets a bit more complicated, it's going to be fuel pump or electrical.

Try this then drop me a line I love a challenge.
 
hi canman.
yes it matters not if it is in the tub or with lugs on attached to hose. it will run and drop into gear (forward and reverse) and rev away perfectly, even when not in gear you can pull on the link and rev away. this problem has been there since i bought it (i did see it working in the tub before i bought it) the first time i took it out it just died under load. as said it would run at about 3knots (in fact i did stay out for a few hours that day staying fairly close) the carbs have been cleaned out as said, there is a good spark with new plugs, I have a compression of 135, 140 & 150 top to bottom.
Ankle biter, it runs well and revs fine, petrol pump has been stripped and all is well. Fuel in the tank was running the last engine without fault ( i only changed it due to it being only 35hp and a little too small, wish i had kept it now) 50:1 mix. It would not do any harm to change it for some new stuff, try anything really. Have not checked the stator as yet, may be one tech step too far for me! but will have a look.
Thanks
 
Most engine problems are electrical but if you have a good spark and it turns over and fires OK, I’d next suspect the fuel system.

Have you tried it with fresh petrol? Does the choke move freely? Do you have any fuel filters that could be blocked?

The engine ticking over in a barrel will not be working very hard compared to opening the throttle to push the boat. Opening the throttle may more of a demand for fuel than the system can deliver. This could be because of blocked filters, leaking diaphragms letting air in when throttle opens. You should also check the condition of the fuel lines for splits or damage that could also let air into the system instead of fuel.

One final thing to check is that there are no blockages on the exhaust side of the engine as back-pressure could stop an engine.

Good luck
 
hi kevin.
Choke is free and butterflys are even when closed. All filters are clear, recently put in line filter just before fuel pump, bulb keeps good pressure once primed. Fuel lines seem OK did cut one as it had a small crack in it at conector, and i did at one point change the "T" connector when it broke in two (thought that might have been the cause actually) have not checked for blockage at exhaust side mind, all seems ok, is there a certain way to do this?
Thanks
Peter
 
hi easy fish
According to evinrude it is 50:1, but i am going to put some new fuel in the tank to eliminate fuel issues, and will try some better octane shell fuel rather than the supermarket crap. if anyone else feel my mix is incorrect please advise.
Peter
 
hollygolly said:
hi kevin.
Choke is free and butterflys are even when closed. All filters are clear, recently put in line filter just before fuel pump, bulb keeps good pressure once primed. Fuel lines seem OK did cut one as it had a small crack in it at conector, and i did at one point change the "T" connector when it broke in two (thought that might have been the cause actually) have not checked for blockage at exhaust side mind, all seems ok, is there a certain way to do this?
Thanks
Peter
Click to expand...

From what you’ve told us, you’re giving the engine a thorough checking over so I’m sure you’ll get it sorted. Sorry I cannot help with any info on checking the exhaust short of a full strip-down which is too severe to suggest yet.
 
Another couple of thoughts. I guess you’ve checked that the air intake is breathing OK.
Could you try pumping the fuel bulb whilst opening the throttle? If the engine problem remains then your fuel pump and lines are probably OK. If the problem goes away, it is a fuelling issue, possibly a dodgy pump or air leak. If it gets worse it suggests you may have a carb problem. You may also spot any fuel leaks from the lines, pump or carbs.
I’d run the 1:50 mix until you get the problem sorted; if the problem is fuelling it will also affect the lubrication that the fuel brings with it.

With that lot checked out, I’d go back to the electrics and check how big a gap the spark will jump. It can look OK on the plug but be weak if the coil or HT leads are on the way out. The timing and advance may need checking too.
 
all these ideas sound like my bag o cr@p 25hp mariner it runs at decent pace on a flat sea but yet when it gets a wee bit choppy it wants to cut in and take off at proper speed and cut out :o i know the way its running when slow its not right and using twice as much fuel at this pace any ideas lads

this is the right speed im sure it shud be doing port logan last summer ... but on a nice flat day the day before east tarbet at the mull it didnt go that fast pmsl
click n play image
 
Just a silly thought Peter, is the throttle control working ok from the remote gear lever! ie; it's opening both carbs together. I'm assuming the control box has a single lever gear/throttle, and a separate idle tick over control lever.
 

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