Cariboo4x4
Member
Good day All. I been trouble shooting my buddies 1986 Onan BGE Emerald I Genset. It resides under a 1991 Itasca motorhome. He bought motorhome off a mutual freind that had it for 6 years. The genset supposedly ran 5-6 years ago and then finally quit running. Motorhome has 167,000 kms so we were thinking genset possibly has low hours. So I took the float bowl off genset and it was all gummed up. I took off carb and soaked it in carb cleaner, removed the clogged pilot jet and main jet. Soaked it all for couple days more and blew it out with compressed air. I could see clearly through jets. Put it all back together and then no spark. Coil tested bad so bought direct replacement coil, new plug wires, and new plugs. It fired up right away yet won t rev out and won t run smoothly. I took carb off and and both jets out. Still all clean. To smooth out engine best as possible I had to screw main jet adjustment screw in ALL THE WAY IN and genset still it ran rough. I expected it would stall with main jet screwed all the way in!
I pulled out the new plugs and both black with soot so definitely running rich.
The carb was spitting fuel slightly out towards air filter (I had air filter off carb). Thinking an intake valve not completely closing? I did compression test and these are the numbers:
Inside cylinder (towards inside of motorhome)
90 psi dry
100 wet
Outside cylinder (flush with outside of motorhome)
100 dry
150 wet
I figure the rings are worn and valves very likely sealing on outside cylinder yet I didn t do valve leakage test due to not having time yesterday. The inside cylinder psi didn t go up much on wet test so maybe its just an intake valve not closing?
Siezed valve or valve spring broke?
Weird thing I discovered is it has a condenser yet no points. I found a service manual online and I have a hard copy parts manual and based on this genset it has electronic ignition so shouldn t have a condenser? It clearly does not have points. I loosened the two screws holding electronic ignition in yet couldn t finagle it out from under flywheel.
I could run the engine on only just one spark plug, either one and it seems to run the same either on both spark plugs or just one or the other. I checked the data in parts manual for coil part number and new coil I bought and it all matches. What is confusing is the new coil says it is not meant to be used for "solid state" ignition. The attached parts photo is of the ignition set up on this engine yet there is a condenser on engine too. Maybe the condenser is the culprit and it should be removed? I ve learned over the years assume nothing that the previous owners have told me is correct. Possibly I need a coil that is for electronic ignition only (solid state)? Solid state same as electronic ignition? The electronic module under flywheel is held onto inside of cover plate with two nuts that I didn t want to remove as I d surely drop nuts down past flywheel. Of course Id use my magnet tool as nuts are about to come off. Cover plate is then fastened to engine so module is held securely in place. I was thinking a person needs to turn flywheel by hand and there is a spot to easily remove module? In parts manual it appears flywheel has no recess for module removal.
Attached is photo of new coil I bought. I didn't use red wire with eyelet attached at either end. I simply connected new coil up exactly as old one. Wire with black tape on it is a black wire that goes to + on coil. All other wires go to -negative post on coil.
So based on what I discovered, I am leaning more towards the inside cylinder intake valve not closing due to fuel spitting out of carb and running rough. I don t think its the condenser and the coil is the direct replacement coil. So any of you have a suggestion for me? I m thinking cylinder leakage test? Its a 30 years old genset and a valve spring replacement on this unit may take how long?
I pulled out the new plugs and both black with soot so definitely running rich.
The carb was spitting fuel slightly out towards air filter (I had air filter off carb). Thinking an intake valve not completely closing? I did compression test and these are the numbers:
Inside cylinder (towards inside of motorhome)
90 psi dry
100 wet
Outside cylinder (flush with outside of motorhome)
100 dry
150 wet
I figure the rings are worn and valves very likely sealing on outside cylinder yet I didn t do valve leakage test due to not having time yesterday. The inside cylinder psi didn t go up much on wet test so maybe its just an intake valve not closing?
Siezed valve or valve spring broke?
Weird thing I discovered is it has a condenser yet no points. I found a service manual online and I have a hard copy parts manual and based on this genset it has electronic ignition so shouldn t have a condenser? It clearly does not have points. I loosened the two screws holding electronic ignition in yet couldn t finagle it out from under flywheel.
I could run the engine on only just one spark plug, either one and it seems to run the same either on both spark plugs or just one or the other. I checked the data in parts manual for coil part number and new coil I bought and it all matches. What is confusing is the new coil says it is not meant to be used for "solid state" ignition. The attached parts photo is of the ignition set up on this engine yet there is a condenser on engine too. Maybe the condenser is the culprit and it should be removed? I ve learned over the years assume nothing that the previous owners have told me is correct. Possibly I need a coil that is for electronic ignition only (solid state)? Solid state same as electronic ignition? The electronic module under flywheel is held onto inside of cover plate with two nuts that I didn t want to remove as I d surely drop nuts down past flywheel. Of course Id use my magnet tool as nuts are about to come off. Cover plate is then fastened to engine so module is held securely in place. I was thinking a person needs to turn flywheel by hand and there is a spot to easily remove module? In parts manual it appears flywheel has no recess for module removal.
Attached is photo of new coil I bought. I didn't use red wire with eyelet attached at either end. I simply connected new coil up exactly as old one. Wire with black tape on it is a black wire that goes to + on coil. All other wires go to -negative post on coil.
So based on what I discovered, I am leaning more towards the inside cylinder intake valve not closing due to fuel spitting out of carb and running rough. I don t think its the condenser and the coil is the direct replacement coil. So any of you have a suggestion for me? I m thinking cylinder leakage test? Its a 30 years old genset and a valve spring replacement on this unit may take how long?
