Service on OMC SeaDrive 115Hp -84

[rcgt78]

Hi,<br /><br />My brother's OMC 115Hp started to bog during acceleration. First the engine did not deliver full power to get the boat up in plane. Now it will give up and die if one tries to accelerate. Otherwise it runs at idle and starting is not a problem. In order to get it up in plane and keep it there one must manually pump priming bulb.<br /><br />Things that have been done:<br /><br />- cleaned fuel filter<br />- changed priming bulb<br />- changed fuel line between filter and VRO<br />- installed water separator<br />- tried another tank<br /><br />So, I believe that either the VRO, primer, carbs or fuel line are causing the problem. <br /><br />Should I try another primer or disconnect it? Would clogged high speed jets let the engine run by pumping priming bulb? What about fuel lines inside Seadrive system, can I open something in order to check them? <br /><br />Is it difficult to change the impeller and t-stats with boat in water? The Seadrive tilts the engine up very high so one could pull the lower unit off. <br /><br />Robbi

 

[rcgt78]

Re: Service on OMC SeaDrive 115Hp -84

I have now cleaned the carbs, primer and checked the VRO by taking it apart.<br /><br />Found that the small filters in the carbs were clogged. I took the boat for a testrun after the cleaning, but same problem. <br /><br />When I opened the VRO I did not find any defective diaphragms, just a little scored shaft and noticed that the oil pump piston was wery hard to move. I did not pull the oil pump piston out of the intake side. Should it be difficult to move the piston or should I be able to pull it out very easily? Any ideas or comments?<br /><br />After I had put it back together the engine seemed to run great at first. It responded to throttle but just when I was going to start accelerating it bogged down. Just like it had lost all fuel pressure.<br /><br />Next I will try to make a pressure/vacuum tester and test the VRO according to a troubleshooting procedure that I found.<br /><br />I still think about the oil pump piston that was sitting very hard. Think that I should open the VRO again and pull that piston out to have a closer look.<br /><br />By the way I have the first version VRO (-84). <br /><br /><br />Robbi

 

[rcgt78]

Re: Service on OMC SeaDrive 115Hp -84

I have now tried another regular fuel pump from Sierra Marine, but the problem is still there.<br /><br />Checked all fuel lines again by pumping fuel with a manual pump. Now I'm sure that there's no leaks in the fuel line.<br /><br />Changed back to the VRO pump again, exact same symptoms. Engine runs very bad at idle. Starting difficulties and sometimes perhaps on only three cylinders. <br /><br />Checked compression that was about 110-120 psi in all cylinders.<br /><br />What about reciculation hoses and valves. How does the recirculation system work and how can I test it?<br /><br />By the way! It seems that the engine is not really charging the battery at all. There was no increase in voltage reading across battery when starting the engine. Shouldn't it be about 13-14V when engine runs and charges the battery. Should a fault in the charging system cause the problems?<br /><br />Comments or suggestions!<br /><br /><br />Best regards,<br />Robbi

 

[snerland]

Re: Service on OMC SeaDrive 115Hp -84

I have the same problem with a Seadrive 2.5L 1982 - I can't get it run faster than 3000 rpm and it sounds like the engine don't run on all cylinders. I have tested the spark plugs, OK. It runs fine at idle. Do you find out what was wrong, or can any help me out?? Thanks!

 

[tashasdaddy]

Re: Service on OMC SeaDrive 115Hp -84

snerland start your own thread, this one is 3 years old.