1983 Evinrude V4 90 HP Low RPM's

skeeter 1 · #1 May 20th, 2006, 07:37 PM

When in the water my motor will not pick up the RPM's, dogs down really bad (almost like it's muffled, I don't think it's the water pump because the water comes out real good through the hose. When I put the flush kit on it at home it will top out the RPM's but backfires through the exhaust within the prop. I have replaced both head gasket, thermostats etc. I also checked the compression and all 4 cylinders are between 105-115 psi. Like I said it seems like the pump/impeller is working both in and out of the water?

Any help is greatly appreciated

Thanks

Walker · #2 May 20th, 2006, 08:20 PM

Well, you've checked compression. The only things left are fuel/air and spark. Your V4 will rev up on muffs on 2 or three cylinders. Check spark and if all is okay there I recommend a teardown and thorough soaking and cleaning of both carbs. Making sure all jets, orifices, and passageways are soparkling clean. Re-assemble with new carb kits. Get fresh fuel and try her.

skeeter 1 · #3 May 21st, 2006, 09:45 AM

I have spark on all 4 plugs and I took the carbs apart and cleaned them, I'll put in fresh fuel and see what happens?

Thanks

skeeter 1 · #4 May 21st, 2006, 09:47 AM

Is there a way to ensure that I am getting the correct amount of spark?

skeeter 1 · #5 May 21st, 2006, 11:10 AM

I just pulled all plugs and noticed that all but one were wet with fuel, the othe one was black and dry? With the plugs out and connected to the wires I get a spark on all, what could cause this?

skeeter 1 · #6 May 21st, 2006, 01:10 PM

Think I found the cause for the back fireing and possibly no RPM, somehow the wires from the power pack to teh coils got reverced, I switched the plug wires on the right side and now teh backfireing is gone. Will see the next time I'm on the water if it's working right.