98 johnson v6 90' 3300 rpm WOT?

[tkast]

God I love boats:<br /><br /> My short tale of woe starts a week ago when my boat world start and then die after 30 seconds. Starts like a champ. So I changed out a fuel line and put a can of dry gas in the tank. This week I started it up again. After a really rough 5 min. it ran nice and smooth. I let it idle for 15 min and called it a sucess. Then today was the big test. Nice day, great weather. It started great and idled well. I started out to the pass and it ran great. After I was out of the nowake zone I started speeding up nice and easy. After the throttle was halfway down there was no change in engine speed or performance. WOT was 3300 when it should have been around 5000. Checked fuel flow(pumped the bulb), turned off engine, started engine, and headed back in. Still @ 3300 rpm. AsI was docking the engine started stalling at low rpms.<br />Any ideas would be helpful<br />Thanks, Thom

 

[OBJ]

Re: 98 johnson v6 90' 3300 rpm WOT?

Welcome to iboats tkast...<br /><br />First thing, get a compression test and see what shape the cylinders are in. Also do a spark test. The spark on each cylinder should jump a 1/2" gap with a white hot strong spark.<br /><br />Normally for your engine, you should be getting 55k to 6k rpm at WOT. You may have been lugging the engine which is not a good thing to do.<br /><br />When was your last tune-up and water pump impeller change out?<br /><br />VRO hooked up and working or disconnected?<br /><br />Does the alarm horn work? You may have been overheating and not know it if the horn isn't working. To test the horn, look on one of the heads for a temp sensor wire coming outta the head. Pull back the rubber boot to expose the knife connector. Turn the ign. key just to on and ground the knife connector to a clean engine ground. The horn should sound a steady tone.<br /><br />I'm sure you'll get somemore help on the forum.

 

[steviecops]

Re: 98 johnson v6 90' 3300 rpm WOT?

Hi<br />I'm no expert by a long way, but here's what happened to me the other day. It might be relevant, it might not.<br /><br />On the way back to the ramp the other day my engine started to surge and lose power. As I slowed down to investigate, it stalled. When I took the cover off, one of my high speed idle orifice plugs had vibrated loose and was leaking fuel as I pumped the bulb. It must have been sucking air whilst underway. <br /><br />Anyway, I tightened it up and everything was fine. Maybe you have a bad connection somewhere?

 

[tkast]

Re: 98 johnson v6 90' 3300 rpm WOT?

I had a complete annual service (all that means to me is $400). It was firing on all cylinders with compression 120-125. The mechanic acted like it was in pretty good shape. the water pump job was included in the service. The dash has 4 alarm lights on it. What prompted me to take it in for service was the fact the engine hot alarm sounded. so I know that thing works. what a racket.

 

[tkast]

Re: 98 johnson v6 90' 3300 rpm WOT?

I had a complete annual service (all that means to me is $400). It was firing on all cylinders with compression 120-125. The mechanic acted like it was in pretty good shape. the water pump job was included in the service. The dash has 4 alarm lights on it. What prompted me to take it in for service was the fact the engine hot alarm sounded. so I know that thing works. what a racket.

 

[OBJ]

Re: 98 johnson v6 90' 3300 rpm WOT?

OK Thom....annual service tuneup done and everything is hunkydorey. Then she starts to shake, rattle and roll, rpms are lost and it runs like crap. That about the jist of it?<br /><br />Sounds like ya' lost spark to one or more cylinders. Probably one whole bank at the end. I would still get the compression tested and check the ignition system for spark. That's the best place to start.

 

[tkast]

Re: 98 johnson v6 90' 3300 rpm WOT?

thanks for all your help. I will check it out

 

[Steve135]

Re: 98 johnson v6 90' 3300 rpm WOT?

Tkast. For what its worth I have spent the last<br />1 1/2 with a similar problem on a 70 HP Rude. Mine was intermitent for a while. Then pretty constant. After changine every part and rebuilding the carbs,and checking all electrics with a meter again and again.(I have a very large supply of used parts). It had gonten worse then ever. It all seemed to be cleared up with the cleaning and resoldering of all grounds starting with the main battery ground. I replaced the whole lug. Then using a dremmel I clean all the coil grounds and some needed to be cut and re soldered back on to the rings.And like a new motor it was fixed. For now? <br />steve

 

[OBJ]

Re: 98 johnson v6 90' 3300 rpm WOT?

By golly that is good advice stinky. A bad ground on a power pack can drive ya' nuts.

 

[clanton]

Re: 98 johnson v6 90' 3300 rpm WOT?

Check the shift switch.

 

[tkast]

Re: 98 johnson v6 90' 3300 rpm WOT?

well I took your advice and the whole bank of cylinders is out. port side. Now what do I do?<br />Thanks in advance

 

[Solittle]

Re: 98 johnson v6 90' 3300 rpm WOT?

Do you have the OMC shop manual for your motor?<br /><br /> http://www.theoutboardwizard.bizhosting.com/parts_service_and_owners_manuals.html

 

[tkast]

Re: 98 johnson v6 90' 3300 rpm WOT?

i do. the thing it seems to me is it may be the powerpack--whatever that is. could it be something else. er a timing sensor or a ground?

 

[OBJ]

Re: 98 johnson v6 90' 3300 rpm WOT?

Thom....don't know which ignition system ya' got...believe there was three different ones but this test should work anyways. Look for the small leads going to the ignition coils. Should be two going to the port side and two going to the starboard side. If you have enough slack in the leads, swap them over. Port to starboard and visversa. Hook up a spark tester and crank the engine. If the spark stays on the starboard side, then the coil pack or coils are bad. If the spark changes to the port side, then the pack is gone. If you don't have enough lead, just swap out the coils. Be nice to know the model number of your engine.<br /><br />Keep us posted.

 

[tkast]

Re: 98 johnson v6 90' 3300 rpm WOT?

to be more specific I have a 1998 60 degree 150hp. osi 2000. I don't have any real testing equipment so I am going by the seat of my pants. The port bank of cylinders is a no spark area. I did disconect the shift sensor and also disconnected the starboard spark plugs. The damm thing started on the first try. Does this rule out a bad powerpack? Do I need a shift sensor to run the boat? Can I run the boat without harming it without a shift sensor? Its Sunday and no stores are open in Naples.

 

[tkast]

Re: 98 johnson v6 90' 3300 rpm WOT?

so I dissconected the shift sensor and it ran GREAT! Many thanks to all who steered me in the right direction. I am so happy I didn't have to spend the $200 at the repair shop. I am trying to get more boating hours for less dollars.