1987 Johnson GT 150 difficult warm starts

[blueghost]

I have a '87 johnson gt 150. I do not use the VRO oil injection, but rather premix (have read the horrar stories) the fuelil (50:1). It starts with minor difficulty when cold (dies a couple of times and runs plenty rich at startup) with plenty of smoke. Warm starts (after running near or at wot for a few minutes) are difficult and engine doesn't want to idle without dieing. Typically I have to open the throttle to get it to start. All plugs appear wet and oily. Have cleaned carbs and ran OMC de-carb through intake. Have not taken compression nor ignition spark tests. I also am not sure about the reed plate condition. Can reeds cause rich mixture at idle? Any suggestions and feedback appreciated.

 

[OBJ]

Re: 1987 Johnson GT 150 difficult warm starts

Hi blueghost....<br /><br />Just a couple background questions...<br /><br />Is this motor new to you or have you owned it a while? If you have owned it a while, is this a new "glich"?<br /><br />If the engine is "new" to you, sounds like a sync and link is needed. This adjustment puts the throttle plate opening and timeing in sync. Need a service manual to do this.<br /><br />When you cleanded the carbs, did you remove ALL jets and blow them out with carb cleaner and follow up with compressed air on ALL carb passages?<br /><br />If a read is damage, you will get a lot of blowback from the carbs and the engine will not idle for squat. Check the carb cover for an excessive amount of fuel laying in the bottom.

 

[blueghost]

Re: 1987 Johnson GT 150 difficult warm starts

OutboardJim,<br /><br />Thanks for your reply.<br /><br />Engine has been in my posession 5 months, however I have asked previous owner/friend if he had these problems. He hadn't noticed it doing this when he last ran it, which leads to the next paragraph.<br /><br />One thing I failed to mention, was that this engine sat for approx 1.5 yrs. <br /><br />I didn't remove all of the jets, but I did check for blockage with cleaner and air. I probably need to revisit the cleaning process. While that far into it I probably need to check reeds because it doesn't idle good at all, and there is, what I would call an excessive amount of oil (due to the gas evaporating and leaving the oil) in the intake cover.<br /><br />I also checked the primer solinoid for proper seal and no leakage, it proved to be ok.<br /><br />I have read about these engines eating power packs, coils, etc. and don't want to overlook the "forest for the trees".<br /><br />I did purchase a factory service manual recently, so I can probably set air-to-fuel-to-timing ratio accordingly. Everything I have done to this point was done prior to getting the manual.<br /><br />Just didn't know where to start with so many possibles.

 

[Hooty]

Re: 1987 Johnson GT 150 difficult warm starts

Like OutboardJim suggested, I'd start with the link and sync. You'll be able to tell pretty quick if it's adjusted correctly or not and it's not that hard to do.<br /><br />c/6<br /><br />Hooty

 

[blueghost]

Re: 1987 Johnson GT 150 difficult warm starts

Thanks Hooty,<br /><br />Sounds like a good place to start, I've got the book out now.<br /><br />I'll let everybody know what the results are after I finish and check out at the lake.<br /><br />Blueghost

 

[Hooty]

Re: 1987 Johnson GT 150 difficult warm starts

Yeah, we like to hear back.<br /><br />g'luck & c/6<br /><br />Hooty

 

[blueghost]

Re: 1987 Johnson GT 150 difficult warm starts

Well guys, I checked compression, 95 pounds on all cyls.<br /><br />I didn't find any problems with the synchronization. Throttle pickup timing was at 7 degrees BTDC and rock solid,carbs are in sync, cam follower pickup adjustment was OK. I only have muffs, and I can't perform the max advance (5000 rpm), as I don't have a wheel. I don't forsee that being a problem since I didn't find anything on the other checks.<br /><br />I suppose my biggest concern is when I have ran the boat for a while, then am at the dock, engine is at running temp, the engine idles rough, dies and doesn't want to start. It will turn over, fire just enough to disengage the starter out, then fails to light off. When I do get it started, I have to lift up on the fast idle lever to keep it running, as it is idling rough. Is this common on these engines?<br /><br />Thanks