90 hp 4-stroke stalling

[chappy77]

I've got a 90 hp on our pontoon boat that stalls at random times. We can be cruising at 3000 rpm or 1500 (it doesn't matter) and then it will just die and when we try starting it back up it won't. The motor turns over fine but it acts like it is flooded. If we let it sit for usually 10 minutes then it will start after a lot of coaxing. The mechanic has looked at it three times and has ruled out not enought air flow to the gas tank. Any other suggestions?

 

[BillP]

Re: 90 hp 4-stroke stalling

I had the exact thing happen to me on my 1996 Mariner (Merc) 50hp 4 stroke. It was like you turned the key off while running and happened 3 times in the first 300 hrs. It quit running at higher speeds twice and once when tilting up for shallow water. It restarted but not always easily. <br /><br />I did all the normal checking and finally found the problem to be at the main harness connector under the cowl. The connector is round and uses hollow roll type pins for the male side. I spread each pin out to a larger diameter and the problem went away. That was in 1997 and never a problem since. Just by looking at the pins you couldn't tell they didn't make good contact...I spread them to make sure and the problem never came back.<br /><br />I'd be very surprised if your 90 merc doesn't share a similar connector. It is mounted on the back of the block (spark plugs on my motor are on the side).

 

[chappy77]

Re: 90 hp 4-stroke stalling

Thanks. I will try that and tell you how it goes.