Bogging Down 150 XR4

"Hello all you pros out there.

"Hello all you pros out there. I have a question about my Mercury XR4 (1990). I can run my boat up the lake for say 10 miles and stop and fish. Re-crank the motor and run say 4 miles and fish. Now the next time I take off the motor will bog down and not get over 6 mph.

I replaced the spark plugs as per another mechanic. Took off up the lake, ran about 10 miles no problems. Crossed the lake about 3 miles and fished. Restarted the motor and bam the same thing, bogged down nothing over 6 mph.

I talked to another mechanic and he said the power packs (switch boxes) were bad. So I spend $400 for the switch boxes and headed back to the lake. Ran about 12 miles, ran about 3 miles and BAM the same thing again.

Any suggestions, I pumped the bulbs, pressed the choke, nothing helps? Now he suggests that I swap out the stator. The mechanic has been servicing motors for about 30 years.

Suggestions please!

BassinBob….

http://bercustompainting.net/"

"Bob, if you swap out the stat

"Bob, if you swap out the stator you can send me your old one along with those "bad" switch boxes

It could well be the problem, giving you a hard time when it heats up. However, you already bought 400 bucks worth of Switch Boxes which almost never fail on Mercs (unlike the power packs on OMC's which are problematic).

Instead of just swapping parts I would invest 30 bucks in a manual and 10 bucks for a cheap multi-meter and check the iginition system out.

It would really be a shame for you to put in a new stator and then find out you have a clogged jet in the carb which can cleaned with a few bucks worth of lacquer thinners......"

"So you think it might be the

"So you think it might be the jets, instead of an electrical problem. This has happend to me on three different occasions. Is there any way to test the switch boxes off the engine, since I still have the two old ones?"

A simple trouble shooting tech

A simple trouble shooting technique is to hook up an inductive pickup timing light.You lay it on a seat and observe the flashing when the motor falters.If # 1 keeps on sparking steadily when it falters then hook up #2 etc etc.You can also have an assistent look into the carburetor bores to compare the amount of fuel coming up the jets. What does a compression test tell you??????

I have not done a compression

I have not done a compression test on the engine. The engine runs fine up to speed and rpms. It only happens after I've run the motor for say 10 to 15 miles. I can start and stop the engine several times during this period without any problems and then the next time I start it up the bog starts.

could possibly be air vent on

could possibly be air vent on tank is plugged or shut

"Have same problem with my 199

"Have same problem with my 1995 135 HP V6. Found a couple of problems at the same time. First, I found a clogged #3 main jet which I cleaned with carb cleaner. After that, it ran much better, but not quite 100% at WOT. Then, I bought a spark tester and found I had no spark on #4 cyl. After checking plug, wires, and coils, I will change switch box this weekend. Good luck."

"Well guys I found the problem

"Well guys I found the problem. It seems that sometime before I bought the boat and motor. Someone had replaced the stator. When they put the new one on, they changed out the screws from machine screws with "wood" screws. The stator worked itself loose and had a wobble in it. I had to replace the stator and flywheel. Was able to re-tap the screw holes and replaced the screws and now everything is fine. My mechanic only charged me $400 for all repairs.

Thanks for the information you guys supplied.

BassinBob....

http://bercustompainting.net/"