OMC Sea Drive 1.6L no power under load

[sgrieve4]

I decided to post this under Johnson & Evenrude since there are not a lot of OMC Sea Drive users left... I have a 1.6L (V4) that was running excelent as I just rebuild the carbs this spring. This 1989 Sea Drive is on a 19 foot 1989 SportCraft. We were running approx 4,800 RPM and it just acted like I turned the key off (fell off plane) but would keep running ... just no power and would not tach up over 2,800 RPM. I stopped and tilted the prop out of the water, no problems there... tried again and same problem. If I start it up and rev it in neutral it will tach up but sounds like it is missing, will not tach up under load. Wondering if REED valves are stuck? Going to do a comp test to see what is happening there, any other thoughts?

BTW: This happened once before and after checking the prop (tilted motor all the way up, then back down) started it up and it ran great.

 

[tashasdaddy]

Re: OMC Sea Drive 1.6L no power under load

check compression and spark with a spark tester. gapped at 7/16 inch. some of the V-4s had 2 power packs one for each side of the motor. if you have lost spark on one side, and have 2 power packs, swap the power packs.

also read this. http://forums.iboats.com/showthread.php?t=330129

 

[sgrieve4]

Re: OMC Sea Drive 1.6L no power under load

I checked spark and had it on all four... now was going to check compression to see if the REED valves are causing a problem. Thanks for the feedback, I will post my results. This setup has just over 400 hours on it.

 

[tashasdaddy]

Re: OMC Sea Drive 1.6L no power under load

does not sound like a reed problem. more like fuel restriction, clogged vent on fuel tank, clogged pickup in fuel tank. overheat problem. contaminated carb.

 

[sgrieve4]

Re: OMC Sea Drive 1.6L no power under load

I did the compression test and all four are between 95 and 100. I did find out #2 cyl is dead (pulled the plug wire with it running and it makes no difference, pulled wire on any of the other three cyl has a huge impact). Bottom line, #2 cyl is the problem, however, it has spark (tested with a timing light and saw spark on plug with it removed) and compression (tested with compression gauge both wet and dry, on a cold and warm engine). Re-confirmed spark and even swapped coil, plug wire and plug with another strong firing cyl. I also sprayed fuel into the carb for #2 with the engine running to see if it would make it come to life, no luck. As mentioned in the beginning of this post, I did a carb re-build in the spring and it was running great. I will confirm all hoses are secure and there are no obstructions, but it sure seems like REED's to me. Even with bad REED valves you can still get compression on a 2 cycle, unlike a 4 cycle with bad valves correct? (I am no expert at 2 cycles so correct me if I am wrong).

I also read your post on ethanol eating up old rubber fuel lines...yep been there done that. I replaced the fuel lines two seasons ago as mine had collapsed inside restricting fuel flow to nearly zero. That is why I decided to rebuild the carbs this spring to make certain the entire fuel system was clear thus my attempt to prevent fuel delivery problems this season. I do have a fuel water separator (yes replaced the filter this year) and an inline fuel filter that is also new/clean.

This model has the VRO2 fuel/oil mixer still installed (I know several people removed that and used mixed gas instead) I pulled the discharge line (the one that goes to the tee on the lines into the carbs) and pumped the primer bulb to confirm gas/oil mixture would discharge out the VRO2 system. That seems to be functioning fine as the other three cylinders are all running well.

 

[tx1961whaler]

Re: OMC Sea Drive 1.6L no power under load

Wouldn't a reed valve problem take out 2 cylinders?

 

[sgrieve4]

Re: OMC Sea Drive 1.6L no power under load

I removed the carbs and intake manifold to ensure all was well with the REEDS. Everything looks good, so I started inspecting the hoses and check valves. One had a lot of debres on it but not sure if that one was serving the #2 cyl. Also rotated engine by hand, and the pistons/rods seem to be ok as best as I can see. Need to get a new intake gasket and put it back together to see if that clears it up.

Any ideas on anything else I need to check before I re-assemble it?

 

[sgrieve4]

Re: OMC Sea Drive 1.6L no power under load

Just to wrap this one up... I put the engine back together and now with all the hoses and check valves operating as they should, it is running great once again.

 

[cdrive09]

Re: OMC Sea Drive 1.6L no power under load

hi there i have the same problem on mine, should i check the hoses first?or do you think it was the intake that was the problem?

 

[karlow1]

Re: OMC Sea Drive 1.6L no power under load

I would think a reed problem would show up on a compression test, right?
With good compression, and good ignition that would mean the fuel supply is questionable. Make sure it's right, fuel = lubrication!

KP

 

[sgrieve4]

Re: OMC Sea Drive 1.6L no power under load

seems like my problem was corrected by cleaning the check valves on the intake manifold (small hoses that enter near the carbs into the intake. There is one for each cyl, service manual states to push alcohol through to clean them if the check valve is not sealing. Three of the four on mine were not correct. I cleaned everything up and re-assembled... solved the dead cyl. issue.