engine problems on 40hp 1990

[frappazza]

first of all i want to say hi everybody!<br /><br />I have an evinrude 25DRL, year 1990, n°2549866,the intake manifold was machined to obtain the original model(737cubic cm)40HP,the reed valve has carbon reeds fitted,the fuel pump is ok,the sparks are new and the water impeller is new too.<br />Carburettors rebuilt at the beginning of this season, maximum jet 49D<br />The outboard is fitted on an inflatable with vtr hull, 4,7 meters long,with flat bottom end and very light weight(120kg the bare hull).<br />The problem is that the maximum rpm with both 15'and 18' pitch is about 4500,untill this limit the trust seems to be good.<br />Recently the engine started to have another problem, during riding at 4000rpm it start to run intermittently,like sombody is playng with turn off wire.<br />The last time i ran the engine it started to show this problem and after a few minutes of idling it turned off and never restarted.<br />Today i'm going to pull the flyweel off and check the ignition system.<br />Soon I'll ceck the compression.<br />What should I've to expect to find?<br />Color of sparks is brown,nearly the same color in both of them.

 

[R.Johnson]

Re: engine problems on 40hp 1990

First do a spark test, and at the same time do a compression test. You need the flywheel on to check ignition out-put. You need to verify that you have spark, fuel, and compression. If you pull the flywheel as a first step,you could find yourself trying to groom a dead horse.

 

[frappazza]

Re: engine problems on 40hp 1990

Thanks for your reply R.Johnson.<br />I've found what i was searching for!<br />one of The wire connecting the ignition module to the ignition coil was interrupted inside the insulating shield,unbelivable,I found that casually,a miracle,probably I've saved the cost of a new ignition module.<br />All the electric components met the stock values for impedance and are well ground insulated.<br />For the compression test I know I need to rebore and get new pistons,I feel it turning the flyweel by hand with both sparks fitted, but in Italy a piston costs 170 euros,and there are only genuine pistons,no aftermarket available.<br />Anyway I'm going to build myself a compression gauge with an old spark hexagon and a tire pression gauge,it reachs 140psi,should work well.<br />As soon as possible I'll post the pressure reading.