1997 Johnoson 175 hp is missing

[gradyrod]

just launched boat and engine runs well for a few minutes then drops off instantly and comes right back up to same rpm. Acceleration is strong and she runs very smoothly until she misses once again. I have new gas, new filters and examined the fuel filter and found no water in the gas. any ideas out there?? Fishing time is near and I don't want to be stuck at the dock!!

I have heard of a possible optical sensor timing issue possible with these motors. Has anyone heard of this ?? If so, what's involved to fix?

Thanks.

Rod
1985 Fisherman 204

 

[BobP]

Rod, does the squeeze bulb collapse when it dies?

Have to look at it at the exact same time it's dying.

 

[gradyrod]

engine miss

Bob-

will have to check this next time I run boat. I guess ur suggesting it could be the fuel pump? I was thinking more towards an ignition problem?

thx.

Rod

 

[BobP]

Well at least there is some things you can try out yourself, you may be best served to take it into OMC dealer for a diagnostic test.

And make sure fuel line hose clamps are snugged up, not loose, and grounds under the cowl are good and at the battery. Spark plug wires on secure at plug and coils.

If the motor worked fine last seaon, may have something to do with winter/spring prep.

The good thing is that it's not an intermittant problem, the worst to find, particularly when you bring it in and all is normal.

 

[gradyrod]

enigne miss

Bob:

Yes, I already contacted the local omc dealer-- he feels it is probably the optical sensor. he says not a big deal to replace, nor is it very expensive!! We'll see what that translates into when he's done!!

Thanks for the feedback!

Rod

 

[sfc2113]

If Carbed, Did you drain out the carb bowls on the carbs before you ran it? If not try it. Maybe some fogging oil in there still messing with the floats.

My rude would not idle more than 5 min until I drained them, then it was fine.

 

[gradyrod]

problem solved-- it was the carbs.

finally got the mechanic to tune the carbs. he went meticulously through all 6 carbs again and again, adjusting the low speed jets with a small screwdriver. no more coughing and almost dying! runs like a top and I hope it stays that way!

thanks all for your help.

Rod