engine now won't start

[daveski1964]

I have a 86 ,85hp force motor ,I tried to decarb my motor by using seafoam ,boat running rough on seafoam ,ran boat about 20 minutes..sprayed carb cleaner in bottom carb ,boat shut off and now will not start,,will turn over as normal but will not start and hear back fire when trying to start.,i guess I did something wrong???????????boat would start run at idle I know I need carb work I just wanted to get my boat started before I took to boat guy for carb rebuild,

 

[Jiggz]

Re: engine now won't start

First check for sparks if there is spark, then the next move is to check for compression. If compression is good then check for fuel related problems. A $5 clear fuel mod installed between the fuel pump outlet and the carbs inlet is indispensable for troubleshooting.

 

[daveski1964]

Re: engine now won't start

I have all new fuel lines from tank to carbs ,put in shut off and new fuel filter,new gas ,new plugs, new coils, good spark..,compression is 100lbs in top two cylinders and 90 in bottom....I had boat in water boat only ran 5mph,i guess carbs needed to be rebuilt ..just wont start now after trying to decarb motor.

 

[Jiggz]

Re: engine now won't start

The compression numbers are a little low although it could just be the gauge itself. If you verified to have good sparks, try spraying fuel into the carbs to see if it will fire. If it fires, then you know you have fuel related problems. With three individual carbs the only thing common with them is the fuel supply. That's why the clear fuel filter mod is very good for this type of troubleshooting. With the clear fuel filter, when you prime the fuel lines with the primer bulb and you can see the filter full of fuel you can rest assure there is fuel going into the carbs. If the engine still would not run, then you know the problem is in the carbs, this is with the assumption you have good sparks. But for three carbs to all go down at the same time is quite unique also.

 

[MickLovin]

Re: engine now won't start

That is around the threshold of being too uneven on compression, if it's around 10% down on one it will make it hard to start, in saying that, you have had it running, but you only got 5mph, which means your high idle jet may be blocked. You don't need a mechanic to do your carbies, Firstly buy a kit, get your manual or youtube rebuilding a carbie. They are pretty simple to rebuild when you have the complete kit, I am due for one myself as mine are leaking from bottom gaskets. Most importantly is to soak them over night, to loosen up varnish from old fuel, I then use an ultrasonic cleaner, like a jewellry cleaner which you can buy pretty cheap. You need to clean out the orifices and jets with possibly a small pipe cleaner type tool. Then blow them out with compressed air, very important to blow them out and to probe the orifices with a pipe cleaner/tool, Think I may have used a paper clip or something similiar that was flexible, but others would have a better way. You can take the jets and needle and seed out, to make sure nothing is stuck in them, you may have found you have dislodged something in your carbie/s which have now blocked them. Make sure after rebuilding them you sync them properly.
I have been told to run my oil a bit higher as I have low cylinder readings too, it was suggested to me to run the motor at 33:1 / 40:1. The gentlemen who advised me to run it at this, has done so on all his two stokes, motor bikes, outboards etc and he states his motors last a lot longer, I would suggest they run a bit rough, but if they still run ok, the mix couldn't hurt.
You only need one carbie to be down to dump it's excess unburnt fuel into the crank. Also have you checked your diaphragm, if it is cracked it will dump fuel into the crank directly causing a flooded scenario, had this one before.
Just an after thought, when I did my old 115hp Suzi carbs, there was a jelly solution floating in the bowl I was soaking them in, I found out later it was more than likely to be ethanol and a varnish build up due to lack of use.

 

[daveski1964]

Re: engine now won't start

I will order carb kit..i think all my problems are my fault I didn't know how to winterize boat over winter.i bought boat at end of last year used boat 4-5 times boat ran fine 35mph all day ..over winter I drained the water and gas out of motor, but I didn't know to drain carb bowles,I hope the carbs are the problem....learned something new about boats,,at a cost to me ....

 

[Jiggz]

Re: engine now won't start

Actually, it is not even recommended to drain the carb bowls for winterization. Instead, you just need to make sure the fuel left in the carbs is of the stabil treated mix. To do this, treat the remaining fuel mix in the tank and then ran the engine long enough that the fuel left in the carbs is of the treated one. If your in-tank is empty you can always use an external tank to ensure only treated fuel is left in the carbs' bowls. Empty bowls results in scaling and dry rotting of seals.

 

[jerryjerry05]

Re: engine now won't start

Profile? Location?
If it ran before the de-carb???
Then the problem is the cylinders have a build up of Seafoam?
Take the plugs out and use a premix of gas and oil and spray in the cylinders.
You might have to clean the plugs a couple of times.
No "high idle jet"There is a high speed jet.
There is a low speed air screw.
The carbs,set at 1 and 1/4 turn out for base setting.
I use Dawn dish soap or Simple Green or the Purple stuff from Autozone.
The hard stuff gets a spray carb cleaner.
If the carb is really dirty then the welch plugs need to be removed.
Get a different comp tester.
Is the test done correct,all plugs out and let it turn over at least 5-6 times?
I use a "tip cleaner" from a welding torch to open clogged jets.
My boat(unfortunatly) sets for a couple/3 months at a time.
I never worry about draining the carbs or even adding any additives.
Now 6mo or longer I'd consider Stabil.